Background task manager (#332)

- [x] New background worker trait - [x] Adapt all current workers to use new API - [x] Command to list currently running workers, and whether they are active, idle, or dead - [x] Error reporting - Optimizations - [x] Merkle updater: several items per iteration - [ ] Use `tokio::task::spawn_blocking` where appropriate so that CPU-intensive tasks don't block other things going on - scrub: - [x] have only one worker with a channel to start/pause/cancel - [x] automatic scrub - [x] ability to view and change tranquility from CLI - [x] persistence of a few info - [ ] Testing Co-authored-by: Alex Auvolat <alex@adnab.me> Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/332 Co-authored-by: Alex <alex@adnab.me> Co-committed-by: Alex <alex@adnab.me>
2022-07-08 13:30:26 +02:00 · 2022-07-08 13:30:26 +02:00 · 4f38cadf6e
commit 4f38cadf6e
parent aab34bfe54
27 changed files with 2050 additions and 738 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -93,6 +93,15 @@ dependencies = [
 "winapi",
 ]
 [[package]]
 name = "autocfg"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0dde43e75fd43e8a1bf86103336bc699aa8d17ad1be60c76c0bdfd4828e19b78"
 dependencies = [
 "autocfg 1.1.0",
 ]
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@ -543,7 +552,7 @@ version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1145cf131a2c6ba0615079ab6a638f7e1973ac9c2634fcbeaaad6114246efe8c"
 dependencies = [
- "autocfg",
+ "autocfg 1.1.0",
 "cfg-if 1.0.0",
 "crossbeam-utils 0.8.8",
 "lazy_static",
@ -959,6 +968,7 @@ dependencies = [
 "futures",
 "futures-util",
 "garage_api",
 "garage_block",
 "garage_db",
 "garage_model 0.7.0",
 "garage_rpc 0.7.0",
@ -984,6 +994,7 @@ dependencies = [
 "sha2",
 "static_init",
 "structopt",
 "timeago",
 "tokio",
 "toml",
 "tracing",
@ -1038,6 +1049,7 @@ dependencies = [
 name = "garage_block"
 version = "0.7.0"
 dependencies = [
 "arc-swap",
 "async-trait",
 "bytes 1.1.0",
 "futures",
@ -1065,11 +1077,11 @@ dependencies = [
 "err-derive 0.3.1",
 "heed",
 "hexdump",
 "log",
 "mktemp",
 "pretty_env_logger",
 "rusqlite",
 "sled",
 "tracing",
 ]
 [[package]]
@ -1258,6 +1270,7 @@ dependencies = [
 name = "garage_util"
 version = "0.7.0"
 dependencies = [
 "async-trait",
 "blake2",
 "chrono",
 "err-derive 0.3.1",
@ -1629,7 +1642,7 @@ version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "282a6247722caba404c065016bbfa522806e51714c34f5dfc3e4a3a46fcb4223"
 dependencies = [
- "autocfg",
+ "autocfg 1.1.0",
 "hashbrown",
 ]
@ -1651,6 +1664,16 @@ dependencies = [
 "serde",
 ]
 [[package]]
 name = "isolang"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "265ef164908329e47e753c769b14cbb27434abf0c41984dca201484022f09ce5"
 dependencies = [
 "phf",
 "phf_codegen",
 ]
 [[package]]
 name = "itertools"
 version = "0.4.19"
@ -1714,7 +1737,7 @@ dependencies = [
 [[package]]
 name = "k2v-client"
-version = "0.1.0"
+version = "0.0.1"
 dependencies = [
 "base64",
 "clap 3.1.18",
@ -1975,7 +1998,7 @@ version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
 dependencies = [
- "autocfg",
+ "autocfg 1.1.0",
 ]
 [[package]]
@ -2137,7 +2160,7 @@ version = "0.1.44"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
 dependencies = [
- "autocfg",
+ "autocfg 1.1.0",
 "num-traits",
 ]
@ -2147,7 +2170,7 @@ version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
 dependencies = [
- "autocfg",
+ "autocfg 1.1.0",
 ]
 [[package]]
@ -2216,7 +2239,7 @@ version = "0.9.72"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7e46109c383602735fa0a2e48dd2b7c892b048e1bf69e5c3b1d804b7d9c203cb"
 dependencies = [
- "autocfg",
+ "autocfg 1.1.0",
 "cc",
 "libc",
 "openssl-src",
@ -2386,6 +2409,44 @@ dependencies = [
 "indexmap",
 ]
 [[package]]
 name = "phf"
 version = "0.7.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b3da44b85f8e8dfaec21adae67f95d93244b2ecf6ad2a692320598dcc8e6dd18"
 dependencies = [
 "phf_shared",
 ]
 [[package]]
 name = "phf_codegen"
 version = "0.7.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b03e85129e324ad4166b06b2c7491ae27fe3ec353af72e72cd1654c7225d517e"
 dependencies = [
 "phf_generator",
 "phf_shared",
 ]
 [[package]]
 name = "phf_generator"
 version = "0.7.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09364cc93c159b8b06b1f4dd8a4398984503483891b0c26b867cf431fb132662"
 dependencies = [
 "phf_shared",
 "rand 0.6.5",
 ]
 [[package]]
 name = "phf_shared"
 version = "0.7.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "234f71a15de2288bcb7e3b6515828d22af7ec8598ee6d24c3b526fa0a80b67a0"
 dependencies = [
 "siphasher",
 ]
 [[package]]
 name = "pin-project"
 version = "0.4.29"
@ -2640,6 +2701,25 @@ dependencies = [
 "winapi",
 ]
 [[package]]
 name = "rand"
 version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
 dependencies = [
 "autocfg 0.1.8",
 "libc",
 "rand_chacha 0.1.1",
 "rand_core 0.4.2",
 "rand_hc",
 "rand_isaac",
 "rand_jitter",
 "rand_os",
 "rand_pcg",
 "rand_xorshift",
 "winapi",
 ]
 [[package]]
 name = "rand"
 version = "0.8.5"
@ -2647,10 +2727,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
 dependencies = [
 "libc",
- "rand_chacha",
+ "rand_chacha 0.3.1",
 "rand_core 0.6.3",
 ]
 [[package]]
 name = "rand_chacha"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"
 dependencies = [
 "autocfg 0.1.8",
 "rand_core 0.3.1",
 ]
 [[package]]
 name = "rand_chacha"
 version = "0.3.1"
@ -2685,6 +2775,77 @@ dependencies = [
 "getrandom",
 ]
 [[package]]
 name = "rand_hc"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
 dependencies = [
 "rand_core 0.3.1",
 ]
 [[package]]
 name = "rand_isaac"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"
 dependencies = [
 "rand_core 0.3.1",
 ]
 [[package]]
 name = "rand_jitter"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"
 dependencies = [
 "libc",
 "rand_core 0.4.2",
 "winapi",
 ]
 [[package]]
 name = "rand_os"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
 dependencies = [
 "cloudabi",
 "fuchsia-cprng",
 "libc",
 "rand_core 0.4.2",
 "rdrand",
 "winapi",
 ]
 [[package]]
 name = "rand_pcg"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "abf9b09b01790cfe0364f52bf32995ea3c39f4d2dd011eac241d2914146d0b44"
 dependencies = [
 "autocfg 0.1.8",
 "rand_core 0.4.2",
 ]
 [[package]]
 name = "rand_xorshift"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cbf7e9e623549b0e21f6e97cf8ecf247c1a8fd2e8a992ae265314300b2455d5c"
 dependencies = [
 "rand_core 0.3.1",
 ]
 [[package]]
 name = "rdrand"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
 dependencies = [
 "rand_core 0.3.1",
 ]
 [[package]]
 name = "redox_syscall"
 version = "0.2.11"
@ -3107,6 +3268,12 @@ dependencies = [
 "libc",
 ]
 [[package]]
 name = "siphasher"
 version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b8de496cf83d4ed58b6be86c3a275b8602f6ffe98d3024a869e124147a9a3ac"
 [[package]]
 name = "slab"
 version = "0.4.5"
@ -3355,6 +3522,16 @@ dependencies = [
 "num_threads",
 ]
 [[package]]
 name = "timeago"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ec32dde57efb15c035ac074118d7f32820451395f28cb0524a01d4e94983b26"
 dependencies = [
 "chrono",
 "isolang",
 ]
 [[package]]
 name = "tinyvec"
 version = "1.5.1"
--- a/Cargo.nix
+++ b/Cargo.nix
@ -172,6 +172,16 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".autocfg."0.1.8" = overridableMkRustCrate (profileName: rec {
    name = "autocfg";
    version = "0.1.8";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "0dde43e75fd43e8a1bf86103336bc699aa8d17ad1be60c76c0bdfd4828e19b78"; };
    dependencies = {
      autocfg = rustPackages."registry+https://github.com/rust-lang/crates.io-index".autocfg."1.1.0" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".autocfg."1.1.0" = overridableMkRustCrate (profileName: rec {
    name = "autocfg";
    version = "1.1.0";
@ -1364,6 +1374,7 @@ in
      futures = rustPackages."registry+https://github.com/rust-lang/crates.io-index".futures."0.3.21" { inherit profileName; };
      futures_util = rustPackages."registry+https://github.com/rust-lang/crates.io-index".futures-util."0.3.21" { inherit profileName; };
      garage_api = rustPackages."unknown".garage_api."0.7.0" { inherit profileName; };
      garage_block = rustPackages."unknown".garage_block."0.7.0" { inherit profileName; };
      garage_db = rustPackages."unknown".garage_db."0.8.0" { inherit profileName; };
      garage_model = rustPackages."unknown".garage_model."0.7.0" { inherit profileName; };
      garage_rpc = rustPackages."unknown".garage_rpc."0.7.0" { inherit profileName; };
@ -1383,6 +1394,7 @@ in
      serde = rustPackages."registry+https://github.com/rust-lang/crates.io-index".serde."1.0.137" { inherit profileName; };
      serde_bytes = rustPackages."registry+https://github.com/rust-lang/crates.io-index".serde_bytes."0.11.5" { inherit profileName; };
      structopt = rustPackages."registry+https://github.com/rust-lang/crates.io-index".structopt."0.3.26" { inherit profileName; };
      timeago = rustPackages."registry+https://github.com/rust-lang/crates.io-index".timeago."0.3.1" { inherit profileName; };
      tokio = rustPackages."registry+https://github.com/rust-lang/crates.io-index".tokio."1.17.0" { inherit profileName; };
      toml = rustPackages."registry+https://github.com/rust-lang/crates.io-index".toml."0.5.8" { inherit profileName; };
      tracing = rustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing."0.1.32" { inherit profileName; };
@ -1458,6 +1470,7 @@ in
    registry = "unknown";
    src = fetchCrateLocal (workspaceSrc + "/src/block");
    dependencies = {
      arc_swap = rustPackages."registry+https://github.com/rust-lang/crates.io-index".arc-swap."1.5.0" { inherit profileName; };
      async_trait = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".async-trait."0.1.52" { profileName = "__noProfile"; };
      bytes = rustPackages."registry+https://github.com/rust-lang/crates.io-index".bytes."1.1.0" { inherit profileName; };
      futures = rustPackages."registry+https://github.com/rust-lang/crates.io-index".futures."0.3.21" { inherit profileName; };
@ -1493,10 +1506,10 @@ in
      err_derive = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".err-derive."0.3.1" { profileName = "__noProfile"; };
      heed = rustPackages."registry+https://github.com/rust-lang/crates.io-index".heed."0.11.0" { inherit profileName; };
      hexdump = rustPackages."registry+https://github.com/rust-lang/crates.io-index".hexdump."0.1.1" { inherit profileName; };
      log = rustPackages."registry+https://github.com/rust-lang/crates.io-index".log."0.4.16" { inherit profileName; };
      ${ if rootFeatures' ? "garage_db" then "pretty_env_logger" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".pretty_env_logger."0.4.0" { inherit profileName; };
      rusqlite = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rusqlite."0.27.0" { inherit profileName; };
      sled = rustPackages."registry+https://github.com/rust-lang/crates.io-index".sled."0.34.7" { inherit profileName; };
      tracing = rustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing."0.1.32" { inherit profileName; };
    };
    devDependencies = {
      mktemp = rustPackages."registry+https://github.com/rust-lang/crates.io-index".mktemp."0.4.1" { inherit profileName; };
@ -1717,6 +1730,7 @@ in
      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_util") "k2v")
    ];
    dependencies = {
      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "async_trait" else null } = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".async-trait."0.1.52" { profileName = "__noProfile"; };
      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "blake2" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".blake2."0.9.2" { inherit profileName; };
      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "chrono" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".chrono."0.4.19" { inherit profileName; };
      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "err_derive" else null } = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".err-derive."0.3.1" { profileName = "__noProfile"; };
@ -2219,6 +2233,22 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".isolang."1.0.0" = overridableMkRustCrate (profileName: rec {
    name = "isolang";
    version = "1.0.0";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "265ef164908329e47e753c769b14cbb27434abf0c41984dca201484022f09ce5"; };
    features = builtins.concatLists [
      [ "default" ]
    ];
    dependencies = {
      phf = rustPackages."registry+https://github.com/rust-lang/crates.io-index".phf."0.7.24" { inherit profileName; };
    };
    buildDependencies = {
      phf_codegen = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".phf_codegen."0.7.24" { profileName = "__noProfile"; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".itertools."0.4.19" = overridableMkRustCrate (profileName: rec {
    name = "itertools";
    version = "0.4.19";
@ -3242,6 +3272,48 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".phf."0.7.24" = overridableMkRustCrate (profileName: rec {
    name = "phf";
    version = "0.7.24";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "b3da44b85f8e8dfaec21adae67f95d93244b2ecf6ad2a692320598dcc8e6dd18"; };
    dependencies = {
      phf_shared = rustPackages."registry+https://github.com/rust-lang/crates.io-index".phf_shared."0.7.24" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".phf_codegen."0.7.24" = overridableMkRustCrate (profileName: rec {
    name = "phf_codegen";
    version = "0.7.24";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "b03e85129e324ad4166b06b2c7491ae27fe3ec353af72e72cd1654c7225d517e"; };
    dependencies = {
      phf_generator = rustPackages."registry+https://github.com/rust-lang/crates.io-index".phf_generator."0.7.24" { inherit profileName; };
      phf_shared = rustPackages."registry+https://github.com/rust-lang/crates.io-index".phf_shared."0.7.24" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".phf_generator."0.7.24" = overridableMkRustCrate (profileName: rec {
    name = "phf_generator";
    version = "0.7.24";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "09364cc93c159b8b06b1f4dd8a4398984503483891b0c26b867cf431fb132662"; };
    dependencies = {
      phf_shared = rustPackages."registry+https://github.com/rust-lang/crates.io-index".phf_shared."0.7.24" { inherit profileName; };
      rand = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand."0.6.5" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".phf_shared."0.7.24" = overridableMkRustCrate (profileName: rec {
    name = "phf_shared";
    version = "0.7.24";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "234f71a15de2288bcb7e3b6515828d22af7ec8598ee6d24c3b526fa0a80b67a0"; };
    dependencies = {
      siphasher = rustPackages."registry+https://github.com/rust-lang/crates.io-index".siphasher."0.2.3" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".pin-project."0.4.29" = overridableMkRustCrate (profileName: rec {
    name = "pin-project";
    version = "0.4.29";
@ -3568,6 +3640,34 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand."0.6.5" = overridableMkRustCrate (profileName: rec {
    name = "rand";
    version = "0.6.5";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"; };
    features = builtins.concatLists [
      [ "alloc" ]
      [ "default" ]
      [ "rand_os" ]
      [ "std" ]
    ];
    dependencies = {
      ${ if hostPlatform.isUnix then "libc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".libc."0.2.121" { inherit profileName; };
      rand_chacha = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_chacha."0.1.1" { inherit profileName; };
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.4.2" { inherit profileName; };
      rand_hc = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_hc."0.1.0" { inherit profileName; };
      rand_isaac = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_isaac."0.1.1" { inherit profileName; };
      rand_jitter = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_jitter."0.1.4" { inherit profileName; };
      rand_os = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_os."0.1.3" { inherit profileName; };
      rand_pcg = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_pcg."0.1.2" { inherit profileName; };
      rand_xorshift = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_xorshift."0.1.1" { inherit profileName; };
      ${ if hostPlatform.isWindows then "winapi" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".winapi."0.3.9" { inherit profileName; };
    };
    buildDependencies = {
      autocfg = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".autocfg."0.1.8" { profileName = "__noProfile"; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand."0.8.5" = overridableMkRustCrate (profileName: rec {
    name = "rand";
    version = "0.8.5";
@ -3590,6 +3690,19 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_chacha."0.1.1" = overridableMkRustCrate (profileName: rec {
    name = "rand_chacha";
    version = "0.1.1";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"; };
    dependencies = {
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.3.1" { inherit profileName; };
    };
    buildDependencies = {
      autocfg = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".autocfg."0.1.8" { profileName = "__noProfile"; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_chacha."0.3.1" = overridableMkRustCrate (profileName: rec {
    name = "rand_chacha";
    version = "0.3.1";
@ -3644,6 +3757,93 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_hc."0.1.0" = overridableMkRustCrate (profileName: rec {
    name = "rand_hc";
    version = "0.1.0";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"; };
    dependencies = {
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.3.1" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_isaac."0.1.1" = overridableMkRustCrate (profileName: rec {
    name = "rand_isaac";
    version = "0.1.1";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"; };
    dependencies = {
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.3.1" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_jitter."0.1.4" = overridableMkRustCrate (profileName: rec {
    name = "rand_jitter";
    version = "0.1.4";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"; };
    features = builtins.concatLists [
      [ "std" ]
    ];
    dependencies = {
      ${ if hostPlatform.parsed.kernel.name == "darwin" || hostPlatform.parsed.kernel.name == "ios" then "libc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".libc."0.2.121" { inherit profileName; };
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.4.2" { inherit profileName; };
      ${ if hostPlatform.parsed.kernel.name == "windows" then "winapi" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".winapi."0.3.9" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_os."0.1.3" = overridableMkRustCrate (profileName: rec {
    name = "rand_os";
    version = "0.1.3";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"; };
    dependencies = {
      ${ if hostPlatform.parsed.kernel.name == "cloudabi" then "cloudabi" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".cloudabi."0.0.3" { inherit profileName; };
      ${ if hostPlatform.parsed.kernel.name == "fuchsia" then "fuchsia_cprng" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".fuchsia-cprng."0.1.1" { inherit profileName; };
      ${ if hostPlatform.isUnix then "libc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".libc."0.2.121" { inherit profileName; };
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.4.2" { inherit profileName; };
      ${ if hostPlatform.parsed.abi.name == "sgx" then "rdrand" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rdrand."0.4.0" { inherit profileName; };
      ${ if hostPlatform.isWindows then "winapi" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".winapi."0.3.9" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_pcg."0.1.2" = overridableMkRustCrate (profileName: rec {
    name = "rand_pcg";
    version = "0.1.2";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "abf9b09b01790cfe0364f52bf32995ea3c39f4d2dd011eac241d2914146d0b44"; };
    dependencies = {
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.4.2" { inherit profileName; };
    };
    buildDependencies = {
      autocfg = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".autocfg."0.1.8" { profileName = "__noProfile"; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rand_xorshift."0.1.1" = overridableMkRustCrate (profileName: rec {
    name = "rand_xorshift";
    version = "0.1.1";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "cbf7e9e623549b0e21f6e97cf8ecf247c1a8fd2e8a992ae265314300b2455d5c"; };
    dependencies = {
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.3.1" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".rdrand."0.4.0" = overridableMkRustCrate (profileName: rec {
    name = "rdrand";
    version = "0.4.0";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"; };
    features = builtins.concatLists [
      [ "default" ]
      [ "std" ]
    ];
    dependencies = {
      rand_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".rand_core."0.3.1" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".redox_syscall."0.2.11" = overridableMkRustCrate (profileName: rec {
    name = "redox_syscall";
    version = "0.2.11";
@ -3738,7 +3938,7 @@ in
    ];
    dependencies = {
      ${ if hostPlatform.parsed.kernel.name == "android" || hostPlatform.parsed.kernel.name == "linux" then "libc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".libc."0.2.121" { inherit profileName; };
-      ${ if hostPlatform.parsed.kernel.name == "dragonfly" || hostPlatform.parsed.kernel.name == "freebsd" || hostPlatform.parsed.kernel.name == "illumos" || hostPlatform.parsed.kernel.name == "netbsd" || hostPlatform.parsed.kernel.name == "openbsd" || hostPlatform.parsed.kernel.name == "solaris" || hostPlatform.parsed.kernel.name == "android" || hostPlatform.parsed.kernel.name == "linux" then "once_cell" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".once_cell."1.10.0" { inherit profileName; };
+      ${ if hostPlatform.parsed.kernel.name == "android" || hostPlatform.parsed.kernel.name == "linux" || hostPlatform.parsed.kernel.name == "dragonfly" || hostPlatform.parsed.kernel.name == "freebsd" || hostPlatform.parsed.kernel.name == "illumos" || hostPlatform.parsed.kernel.name == "netbsd" || hostPlatform.parsed.kernel.name == "openbsd" || hostPlatform.parsed.kernel.name == "solaris" then "once_cell" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".once_cell."1.10.0" { inherit profileName; };
      ${ if hostPlatform.parsed.cpu.name == "i686" || hostPlatform.parsed.cpu.name == "x86_64" || (hostPlatform.parsed.cpu.name == "aarch64" || hostPlatform.parsed.cpu.name == "armv6l" || hostPlatform.parsed.cpu.name == "armv7l") && (hostPlatform.parsed.kernel.name == "android" || hostPlatform.parsed.kernel.name == "fuchsia" || hostPlatform.parsed.kernel.name == "linux") then "spin" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".spin."0.5.2" { inherit profileName; };
      untrusted = rustPackages."registry+https://github.com/rust-lang/crates.io-index".untrusted."0.7.1" { inherit profileName; };
      ${ if hostPlatform.parsed.cpu.name == "wasm32" && hostPlatform.parsed.vendor.name == "unknown" && hostPlatform.parsed.kernel.name == "unknown" && hostPlatform.parsed.abi.name == "" then "web_sys" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".web-sys."0.3.56" { inherit profileName; };
@ -4213,6 +4413,13 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".siphasher."0.2.3" = overridableMkRustCrate (profileName: rec {
    name = "siphasher";
    version = "0.2.3";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "0b8de496cf83d4ed58b6be86c3a275b8602f6ffe98d3024a869e124147a9a3ac"; };
  });
  "registry+https://github.com/rust-lang/crates.io-index".slab."0.4.5" = overridableMkRustCrate (profileName: rec {
    name = "slab";
    version = "0.4.5";
@ -4327,7 +4534,7 @@ in
    ];
    dependencies = {
      bitflags = rustPackages."registry+https://github.com/rust-lang/crates.io-index".bitflags."1.3.2" { inherit profileName; };
-      ${ if hostPlatform.parsed.kernel.name == "linux" || hostPlatform.parsed.kernel.name == "android" then "libc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".libc."0.2.121" { inherit profileName; };
+      ${ if hostPlatform.parsed.kernel.name == "android" || hostPlatform.parsed.kernel.name == "linux" then "libc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".libc."0.2.121" { inherit profileName; };
      ${ if !(hostPlatform.parsed.kernel.name == "linux" || hostPlatform.parsed.kernel.name == "android") then "parking_lot" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".parking_lot."0.11.2" { inherit profileName; };
      ${ if !(hostPlatform.parsed.kernel.name == "linux" || hostPlatform.parsed.kernel.name == "android") then "parking_lot_core" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".parking_lot_core."0.8.5" { inherit profileName; };
      static_init_macro = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".static_init_macro."1.0.2" { profileName = "__noProfile"; };
@ -4410,7 +4617,7 @@ in
      [ "proc-macro" ]
      [ "quote" ]
      [ "visit" ]
-      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client") "visit-mut")
+      [ "visit-mut" ]
    ];
    dependencies = {
      proc_macro2 = rustPackages."registry+https://github.com/rust-lang/crates.io-index".proc-macro2."1.0.36" { inherit profileName; };
@ -4539,6 +4746,23 @@ in
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".timeago."0.3.1" = overridableMkRustCrate (profileName: rec {
    name = "timeago";
    version = "0.3.1";
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "6ec32dde57efb15c035ac074118d7f32820451395f28cb0524a01d4e94983b26"; };
    features = builtins.concatLists [
      [ "chrono" ]
      [ "default" ]
      [ "isolang" ]
      [ "translations" ]
    ];
    dependencies = {
      chrono = rustPackages."registry+https://github.com/rust-lang/crates.io-index".chrono."0.4.19" { inherit profileName; };
      isolang = rustPackages."registry+https://github.com/rust-lang/crates.io-index".isolang."1.0.0" { inherit profileName; };
    };
  });
  "registry+https://github.com/rust-lang/crates.io-index".tinyvec."1.5.1" = overridableMkRustCrate (profileName: rec {
    name = "tinyvec";
    version = "1.5.1";
@ -4883,19 +5107,19 @@ in
    registry = "registry+https://github.com/rust-lang/crates.io-index";
    src = fetchCratesIo { inherit name version; sha256 = "4a1bdf54a7c28a2bbf701e1d2233f6c77f473486b94bee4f9678da5a148dca7f"; };
    features = builtins.concatLists [
-      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client") "attributes")
+      [ "attributes" ]
-      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client") "default")
+      [ "default" ]
      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_web") "log")
      (lib.optional (rootFeatures' ? "garage") "log-always")
-      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client") "std")
+      [ "std" ]
-      (lib.optional (rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client") "tracing-attributes")
+      [ "tracing-attributes" ]
    ];
    dependencies = {
-      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "cfg_if" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".cfg-if."1.0.0" { inherit profileName; };
+      cfg_if = rustPackages."registry+https://github.com/rust-lang/crates.io-index".cfg-if."1.0.0" { inherit profileName; };
      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_web" then "log" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".log."0.4.16" { inherit profileName; };
-      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "pin_project_lite" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".pin-project-lite."0.2.8" { inherit profileName; };
+      pin_project_lite = rustPackages."registry+https://github.com/rust-lang/crates.io-index".pin-project-lite."0.2.8" { inherit profileName; };
-      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "tracing_attributes" else null } = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing-attributes."0.1.20" { profileName = "__noProfile"; };
+      tracing_attributes = buildRustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing-attributes."0.1.20" { profileName = "__noProfile"; };
-      ${ if rootFeatures' ? "garage" || rootFeatures' ? "garage_api" || rootFeatures' ? "garage_block" || rootFeatures' ? "garage_model" || rootFeatures' ? "garage_rpc" || rootFeatures' ? "garage_table" || rootFeatures' ? "garage_util" || rootFeatures' ? "garage_web" || rootFeatures' ? "k2v-client" then "tracing_core" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing-core."0.1.23" { inherit profileName; };
+      tracing_core = rustPackages."registry+https://github.com/rust-lang/crates.io-index".tracing-core."0.1.23" { inherit profileName; };
    };
  });
@ -5330,10 +5554,10 @@ in
      [ "default" ]
    ];
    dependencies = {
-      ${ if hostPlatform.config == "aarch64-uwp-windows-msvc" || hostPlatform.config == "aarch64-pc-windows-msvc" then "windows_aarch64_msvc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_aarch64_msvc."0.32.0" { inherit profileName; };
+      ${ if hostPlatform.config == "aarch64-pc-windows-msvc" || hostPlatform.config == "aarch64-uwp-windows-msvc" then "windows_aarch64_msvc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_aarch64_msvc."0.32.0" { inherit profileName; };
-      ${ if hostPlatform.config == "i686-pc-windows-gnu" || hostPlatform.config == "i686-uwp-windows-gnu" then "windows_i686_gnu" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_i686_gnu."0.32.0" { inherit profileName; };
+      ${ if hostPlatform.config == "i686-uwp-windows-gnu" || hostPlatform.config == "i686-pc-windows-gnu" then "windows_i686_gnu" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_i686_gnu."0.32.0" { inherit profileName; };
      ${ if hostPlatform.config == "i686-uwp-windows-msvc" || hostPlatform.config == "i686-pc-windows-msvc" then "windows_i686_msvc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_i686_msvc."0.32.0" { inherit profileName; };
-      ${ if hostPlatform.config == "x86_64-uwp-windows-gnu" || hostPlatform.config == "x86_64-pc-windows-gnu" then "windows_x86_64_gnu" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_x86_64_gnu."0.32.0" { inherit profileName; };
+      ${ if hostPlatform.config == "x86_64-pc-windows-gnu" || hostPlatform.config == "x86_64-uwp-windows-gnu" then "windows_x86_64_gnu" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_x86_64_gnu."0.32.0" { inherit profileName; };
      ${ if hostPlatform.config == "x86_64-uwp-windows-msvc" || hostPlatform.config == "x86_64-pc-windows-msvc" then "windows_x86_64_msvc" else null } = rustPackages."registry+https://github.com/rust-lang/crates.io-index".windows_x86_64_msvc."0.32.0" { inherit profileName; };
    };
  });
--- a/22
+++ b/22
@ -1,13 +1,27 @@
-.PHONY: doc all release shell
+.PHONY: doc all release shell run1 run2 run3
 all:
 	clear; cargo build --all-features
 doc:
 	cd doc/book; mdbook build
 release:
 	nix-build --arg release true
 shell:
 	nix-shell
 # ----
 run1:
 	RUST_LOG=garage=debug ./target/debug/garage -c tmp/config1.toml server
 run1rel:
 	RUST_LOG=garage=debug ./target/release/garage -c tmp/config1.toml server
 run2:
 	RUST_LOG=garage=debug ./target/debug/garage -c tmp/config2.toml server
 run2rel:
 	RUST_LOG=garage=debug ./target/release/garage -c tmp/config2.toml server
 run3:
 	RUST_LOG=garage=debug ./target/debug/garage -c tmp/config3.toml server
 run3rel:
 	RUST_LOG=garage=debug ./target/release/garage -c tmp/config3.toml server
--- a/src/block/Cargo.toml
+++ b/src/block/Cargo.toml
@ -21,6 +21,7 @@ garage_table = { version = "0.7.0", path = "../table" }
 opentelemetry = "0.17"
 arc-swap = "1.5"
 async-trait = "0.1.7"
 bytes = "1.0"
 hex = "0.4"
--- a/src/block/lib.rs
+++ b/src/block/lib.rs
@ -2,6 +2,7 @@
 extern crate tracing;
 pub mod manager;
 pub mod repair;
 mod block;
 mod metrics;
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@ -1,18 +1,17 @@
 use core::ops::Bound;
 use std::convert::TryInto;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::Duration;
 use arc_swap::ArcSwapOption;
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 use futures::future::*;
 use futures::select;
 use tokio::fs;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
-use tokio::sync::{watch, Mutex, Notify};
+use tokio::select;
 use tokio::sync::{mpsc, watch, Mutex, Notify};
 use opentelemetry::{
 	trace::{FutureExt as OtelFutureExt, TraceContextExt, Tracer},
@ -22,6 +21,7 @@ use opentelemetry::{
 use garage_db as db;
 use garage_db::counted_tree_hack::CountedTree;
 use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::metrics::RecordDuration;
@ -36,6 +36,7 @@ use garage_table::replication::{TableReplication, TableShardedReplication};
 use crate::block::*;
 use crate::metrics::*;
 use crate::rc::*;
 use crate::repair::*;
 /// Size under which data will be stored inlined in database instead of as files
 pub const INLINE_THRESHOLD: usize = 3072;
@ -93,16 +94,18 @@ pub struct BlockManager {
 	mutation_lock: Mutex<BlockManagerLocked>,
-	rc: BlockRc,
+	pub(crate) rc: BlockRc,
 	resync_queue: CountedTree,
 	resync_notify: Notify,
 	resync_errors: CountedTree,
-	system: Arc<System>,
+	pub(crate) system: Arc<System>,
 	endpoint: Arc<Endpoint<BlockRpc, Self>>,
 	metrics: BlockManagerMetrics,
 	tx_scrub_command: ArcSwapOption<mpsc::Sender<ScrubWorkerCommand>>,
 }
 // This custom struct contains functions that must only be ran
@ -110,6 +113,12 @@ pub struct BlockManager {
 // it INSIDE a Mutex.
 struct BlockManagerLocked();
 enum ResyncIterResult {
 	BusyDidSomething,
 	BusyDidNothing,
 	IdleFor(Duration),
 }
 impl BlockManager {
 	pub fn new(
 		db: &db::Db,
@ -157,10 +166,11 @@ impl BlockManager {
 			system,
 			endpoint,
 			metrics,
 			tx_scrub_command: ArcSwapOption::new(None),
 		});
 		block_manager.endpoint.set_handler(block_manager.clone());
-		block_manager.clone().spawn_background_worker();
+		block_manager.clone().spawn_background_workers();
 		block_manager
 	}
@ -218,90 +228,6 @@ impl BlockManager {
 		Ok(())
 	}
 	/// Launch the repair procedure on the data store
 	///
 	/// This will list all blocks locally present, as well as those
 	/// that are required because of refcount > 0, and will try
 	/// to fix any mismatch between the two.
 	pub async fn repair_data_store(&self, must_exit: &watch::Receiver<bool>) -> Result<(), Error> {
 		// 1. Repair blocks from RC table.
 		let mut next_start: Option<Hash> = None;
 		loop {
 			// We have to do this complicated two-step process where we first read a bunch
 			// of hashes from the RC table, and then insert them in the to-resync queue,
 			// because of SQLite. Basically, as long as we have an iterator on a DB table,
 			// we can't do anything else on the DB. The naive approach (which we had previously)
 			// of just iterating on the RC table and inserting items one to one in the resync
 			// queue can't work here, it would just provoke a deadlock in the SQLite adapter code.
 			// This is mostly because the Rust bindings for SQLite assume a worst-case scenario
 			// where SQLite is not compiled in thread-safe mode, so we have to wrap everything
 			// in a mutex (see db/sqlite_adapter.rs and discussion in PR #322).
 			let mut batch_of_hashes = vec![];
 			let start_bound = match next_start.as_ref() {
 				None => Bound::Unbounded,
 				Some(x) => Bound::Excluded(x.as_slice()),
 			};
 			for entry in self
 				.rc
 				.rc
 				.range::<&[u8], _>((start_bound, Bound::Unbounded))?
 			{
 				let (hash, _) = entry?;
 				let hash = Hash::try_from(&hash[..]).unwrap();
 				batch_of_hashes.push(hash);
 				if batch_of_hashes.len() >= 1000 {
 					break;
 				}
 			}
 			if batch_of_hashes.is_empty() {
 				break;
 			}
 			for hash in batch_of_hashes.into_iter() {
 				self.put_to_resync(&hash, Duration::from_secs(0))?;
 				next_start = Some(hash)
 			}
 			if *must_exit.borrow() {
 				return Ok(());
 			}
 		}
 		// 2. Repair blocks actually on disk
 		// Lists all blocks on disk and adds them to the resync queue.
 		// This allows us to find blocks we are storing but don't actually need,
 		// so that we can offload them if necessary and then delete them locally.
 		self.for_each_file(
 			(),
 			move |_, hash| async move {
 				self.put_to_resync(&hash, Duration::from_secs(0))
 					.map_err(Into::into)
 			},
 			must_exit,
 		)
 		.await
 	}
 	/// Verify integrity of each block on disk. Use `speed_limit` to limit the load generated by
 	/// this function.
 	pub async fn scrub_data_store(
 		&self,
 		must_exit: &watch::Receiver<bool>,
 		tranquility: u32,
 	) -> Result<(), Error> {
 		let tranquilizer = Tranquilizer::new(30);
 		self.for_each_file(
 			tranquilizer,
 			move |mut tranquilizer, hash| async move {
 				let _ = self.read_block(&hash).await;
 				tranquilizer.tranquilize(tranquility).await;
 				Ok(tranquilizer)
 			},
 			must_exit,
 		)
 		.await
 	}
 	/// Get lenght of resync queue
 	pub fn resync_queue_len(&self) -> Result<usize, Error> {
 		// This currently can't return an error because the CountedTree hack
@ -321,6 +247,17 @@ impl BlockManager {
 		Ok(self.rc.rc.len()?)
 	}
 	/// Send command to start/stop/manager scrub worker
 	pub async fn send_scrub_command(&self, cmd: ScrubWorkerCommand) {
 		let _ = self
 			.tx_scrub_command
 			.load()
 			.as_ref()
 			.unwrap()
 			.send(cmd)
 			.await;
 	}
 	//// ----- Managing the reference counter ----
 	/// Increment the number of time a block is used, putting it to resynchronization if it is
@ -390,7 +327,7 @@ impl BlockManager {
 	}
 	/// Read block from disk, verifying it's integrity
-	async fn read_block(&self, hash: &Hash) -> Result<BlockRpc, Error> {
+	pub(crate) async fn read_block(&self, hash: &Hash) -> Result<BlockRpc, Error> {
 		let data = self
 			.read_block_internal(hash)
 			.bound_record_duration(&self.metrics.block_read_duration)
@ -554,18 +491,23 @@ impl BlockManager {
 	// for times that are earlier than the exponential back-off delay
 	// is a natural condition that is handled properly).
-	fn spawn_background_worker(self: Arc<Self>) {
+	fn spawn_background_workers(self: Arc<Self>) {
 		// Launch a background workers for background resync loop processing
 		let background = self.system.background.clone();
 		let worker = ResyncWorker::new(self.clone());
 		tokio::spawn(async move {
 			tokio::time::sleep(Duration::from_secs(10)).await;
-			background.spawn_worker("block resync worker".into(), move |must_exit| {
+			background.spawn_worker(worker);
 				self.resync_loop(must_exit)
 			});
 		});
 		// Launch a background worker for data store scrubs
 		let (scrub_tx, scrub_rx) = mpsc::channel(1);
 		self.tx_scrub_command.store(Some(Arc::new(scrub_tx)));
 		let scrub_worker = ScrubWorker::new(self.clone(), scrub_rx);
 		self.system.background.spawn_worker(scrub_worker);
 	}
-	fn put_to_resync(&self, hash: &Hash, delay: Duration) -> db::Result<()> {
+	pub(crate) fn put_to_resync(&self, hash: &Hash, delay: Duration) -> db::Result<()> {
 		let when = now_msec() + delay.as_millis() as u64;
 		self.put_to_resync_at(hash, when)
 	}
@ -579,37 +521,7 @@ impl BlockManager {
 		Ok(())
 	}
-	async fn resync_loop(self: Arc<Self>, mut must_exit: watch::Receiver<bool>) {
+	async fn resync_iter(&self) -> Result<ResyncIterResult, db::Error> {
 		let mut tranquilizer = Tranquilizer::new(30);
 		while !*must_exit.borrow() {
 			match self.resync_iter(&mut must_exit).await {
 				Ok(true) => {
 					tranquilizer.tranquilize(self.background_tranquility).await;
 				}
 				Ok(false) => {
 					tranquilizer.reset();
 				}
 				Err(e) => {
 					// The errors that we have here are only Sled errors
 					// We don't really know how to handle them so just ¯\_(ツ)_/¯
 					// (there is kind of an assumption that Sled won't error on us,
 					// if it does there is not much we can do -- TODO should we just panic?)
 					error!(
 						"Could not do a resync iteration: {} (this is a very bad error)",
 						e
 					);
 					tranquilizer.reset();
 				}
 			}
 		}
 	}
 	// The result of resync_iter is:
 	// - Ok(true) -> a block was processed (successfully or not)
 	// - Ok(false) -> no block was processed, but we are ready for the next iteration
 	// - Err(_) -> a Sled error occurred when reading/writing from resync_queue/resync_errors
 	async fn resync_iter(&self, must_exit: &mut watch::Receiver<bool>) -> Result<bool, db::Error> {
 		if let Some((time_bytes, hash_bytes)) = self.resync_queue.first()? {
 			let time_msec = u64::from_be_bytes(time_bytes[0..8].try_into().unwrap());
 			let now = now_msec();
@ -629,7 +541,7 @@ impl BlockManager {
 						// (we want to do the remove after the insert to ensure
 						// that the item is not lost if we crash in-between)
 						self.resync_queue.remove(time_bytes)?;
-						return Ok(false);
+						return Ok(ResyncIterResult::BusyDidNothing);
 					}
 				}
@ -676,15 +588,11 @@ impl BlockManager {
 					self.resync_queue.remove(time_bytes)?;
 				}
-				Ok(true)
+				Ok(ResyncIterResult::BusyDidSomething)
 			} else {
-				let delay = tokio::time::sleep(Duration::from_millis(time_msec - now));
+				Ok(ResyncIterResult::IdleFor(Duration::from_millis(
-				select! {
+					time_msec - now,
-					_ = delay.fuse() => {},
+				)))
 					_ = self.resync_notify.notified().fuse() => {},
 					_ = must_exit.changed().fuse() => {},
 				}
 				Ok(false)
 			}
 		} else {
 			// Here we wait either for a notification that an item has been
@ -693,13 +601,7 @@ impl BlockManager {
 			// between the time we checked the queue and the first poll
 			// to resync_notify.notified(): if that happens, we'll just loop
 			// back 10 seconds later, which is fine.
-			let delay = tokio::time::sleep(Duration::from_secs(10));
+			Ok(ResyncIterResult::IdleFor(Duration::from_secs(10)))
 			select! {
 				_ = delay.fuse() => {},
 				_ = self.resync_notify.notified().fuse() => {},
 				_ = must_exit.changed().fuse() => {},
 			}
 			Ok(false)
 		}
 	}
@ -814,72 +716,6 @@ impl BlockManager {
 		Ok(())
 	}
 	// ---- Utility: iteration on files in the data directory ----
 	async fn for_each_file<F, Fut, State>(
 		&self,
 		state: State,
 		mut f: F,
 		must_exit: &watch::Receiver<bool>,
 	) -> Result<(), Error>
 	where
 		F: FnMut(State, Hash) -> Fut + Send,
 		Fut: Future<Output = Result<State, Error>> + Send,
 		State: Send,
 	{
 		self.for_each_file_rec(&self.data_dir, state, &mut f, must_exit)
 			.await
 			.map(|_| ())
 	}
 	fn for_each_file_rec<'a, F, Fut, State>(
 		&'a self,
 		path: &'a Path,
 		mut state: State,
 		f: &'a mut F,
 		must_exit: &'a watch::Receiver<bool>,
 	) -> BoxFuture<'a, Result<State, Error>>
 	where
 		F: FnMut(State, Hash) -> Fut + Send,
 		Fut: Future<Output = Result<State, Error>> + Send,
 		State: Send + 'a,
 	{
 		async move {
 			let mut ls_data_dir = fs::read_dir(path).await?;
 			while let Some(data_dir_ent) = ls_data_dir.next_entry().await? {
 				if *must_exit.borrow() {
 					break;
 				}
 				let name = data_dir_ent.file_name();
 				let name = if let Ok(n) = name.into_string() {
 					n
 				} else {
 					continue;
 				};
 				let ent_type = data_dir_ent.file_type().await?;
 				let name = name.strip_suffix(".zst").unwrap_or(&name);
 				if name.len() == 2 && hex::decode(&name).is_ok() && ent_type.is_dir() {
 					state = self
 						.for_each_file_rec(&data_dir_ent.path(), state, f, must_exit)
 						.await?;
 				} else if name.len() == 64 {
 					let hash_bytes = if let Ok(h) = hex::decode(&name) {
 						h
 					} else {
 						continue;
 					};
 					let mut hash = [0u8; 32];
 					hash.copy_from_slice(&hash_bytes[..]);
 					state = f(state, hash.into()).await?;
 				}
 			}
 			Ok(state)
 		}
 		.boxed()
 	}
 }
 #[async_trait]
@ -898,6 +734,77 @@ impl EndpointHandler<BlockRpc> for BlockManager {
 	}
 }
 struct ResyncWorker {
 	manager: Arc<BlockManager>,
 	tranquilizer: Tranquilizer,
 	next_delay: Duration,
 }
 impl ResyncWorker {
 	fn new(manager: Arc<BlockManager>) -> Self {
 		Self {
 			manager,
 			tranquilizer: Tranquilizer::new(30),
 			next_delay: Duration::from_secs(10),
 		}
 	}
 }
 #[async_trait]
 impl Worker for ResyncWorker {
 	fn name(&self) -> String {
 		"Block resync worker".into()
 	}
 	fn info(&self) -> Option<String> {
 		let mut ret = vec![];
 		let qlen = self.manager.resync_queue_len().unwrap_or(0);
 		let elen = self.manager.resync_errors_len().unwrap_or(0);
 		if qlen > 0 {
 			ret.push(format!("{} blocks in queue", qlen));
 		}
 		if elen > 0 {
 			ret.push(format!("{} blocks in error state", elen));
 		}
 		if !ret.is_empty() {
 			Some(ret.join(", "))
 		} else {
 			None
 		}
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		self.tranquilizer.reset();
 		match self.manager.resync_iter().await {
 			Ok(ResyncIterResult::BusyDidSomething) => Ok(self
 				.tranquilizer
 				.tranquilize_worker(self.manager.background_tranquility)),
 			Ok(ResyncIterResult::BusyDidNothing) => Ok(WorkerState::Busy),
 			Ok(ResyncIterResult::IdleFor(delay)) => {
 				self.next_delay = delay;
 				Ok(WorkerState::Idle)
 			}
 			Err(e) => {
 				// The errors that we have here are only Sled errors
 				// We don't really know how to handle them so just ¯\_(ツ)_/¯
 				// (there is kind of an assumption that Sled won't error on us,
 				// if it does there is not much we can do -- TODO should we just panic?)
 				// Here we just give the error to the worker manager,
 				// it will print it to the logs and increment a counter
 				Err(e.into())
 			}
 		}
 	}
 	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
 		select! {
 			_ = tokio::time::sleep(self.next_delay) => (),
 			_ = self.manager.resync_notify.notified() => (),
 		};
 		WorkerState::Busy
 	}
 }
 struct BlockStatus {
 	exists: bool,
 	needed: RcEntry,
--- a/src/block/repair.rs
+++ b/src/block/repair.rs
@ -0,0 +1,444 @@
 use core::ops::Bound;
 use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::Duration;
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 use tokio::fs;
 use tokio::select;
 use tokio::sync::mpsc;
 use tokio::sync::watch;
 use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::persister::Persister;
 use garage_util::time::*;
 use garage_util::tranquilizer::Tranquilizer;
 use crate::manager::*;
 const SCRUB_INTERVAL: Duration = Duration::from_secs(3600 * 24 * 30); // full scrub every 30 days
 pub struct RepairWorker {
 	manager: Arc<BlockManager>,
 	next_start: Option<Hash>,
 	block_iter: Option<BlockStoreIterator>,
 }
 impl RepairWorker {
 	pub fn new(manager: Arc<BlockManager>) -> Self {
 		Self {
 			manager,
 			next_start: None,
 			block_iter: None,
 		}
 	}
 }
 #[async_trait]
 impl Worker for RepairWorker {
 	fn name(&self) -> String {
 		"Block repair worker".into()
 	}
 	fn info(&self) -> Option<String> {
 		match self.block_iter.as_ref() {
 			None => {
 				let idx_bytes = self
 					.next_start
 					.as_ref()
 					.map(|x| x.as_slice())
 					.unwrap_or(&[]);
 				let idx_bytes = if idx_bytes.len() > 4 {
 					&idx_bytes[..4]
 				} else {
 					idx_bytes
 				};
 				Some(format!("Phase 1: {}", hex::encode(idx_bytes)))
 			}
 			Some(bi) => Some(format!("Phase 2: {:.2}% done", bi.progress() * 100.)),
 		}
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		match self.block_iter.as_mut() {
 			None => {
 				// Phase 1: Repair blocks from RC table.
 				// We have to do this complicated two-step process where we first read a bunch
 				// of hashes from the RC table, and then insert them in the to-resync queue,
 				// because of SQLite. Basically, as long as we have an iterator on a DB table,
 				// we can't do anything else on the DB. The naive approach (which we had previously)
 				// of just iterating on the RC table and inserting items one to one in the resync
 				// queue can't work here, it would just provoke a deadlock in the SQLite adapter code.
 				// This is mostly because the Rust bindings for SQLite assume a worst-case scenario
 				// where SQLite is not compiled in thread-safe mode, so we have to wrap everything
 				// in a mutex (see db/sqlite_adapter.rs and discussion in PR #322).
 				// TODO: maybe do this with tokio::task::spawn_blocking ?
 				let mut batch_of_hashes = vec![];
 				let start_bound = match self.next_start.as_ref() {
 					None => Bound::Unbounded,
 					Some(x) => Bound::Excluded(x.as_slice()),
 				};
 				for entry in self
 					.manager
 					.rc
 					.rc
 					.range::<&[u8], _>((start_bound, Bound::Unbounded))?
 				{
 					let (hash, _) = entry?;
 					let hash = Hash::try_from(&hash[..]).unwrap();
 					batch_of_hashes.push(hash);
 					if batch_of_hashes.len() >= 1000 {
 						break;
 					}
 				}
 				if batch_of_hashes.is_empty() {
 					// move on to phase 2
 					self.block_iter = Some(BlockStoreIterator::new(&self.manager));
 					return Ok(WorkerState::Busy);
 				}
 				for hash in batch_of_hashes.into_iter() {
 					self.manager.put_to_resync(&hash, Duration::from_secs(0))?;
 					self.next_start = Some(hash)
 				}
 				Ok(WorkerState::Busy)
 			}
 			Some(bi) => {
 				// Phase 2: Repair blocks actually on disk
 				// Lists all blocks on disk and adds them to the resync queue.
 				// This allows us to find blocks we are storing but don't actually need,
 				// so that we can offload them if necessary and then delete them locally.
 				if let Some(hash) = bi.next().await? {
 					self.manager.put_to_resync(&hash, Duration::from_secs(0))?;
 					Ok(WorkerState::Busy)
 				} else {
 					Ok(WorkerState::Done)
 				}
 			}
 		}
 	}
 	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
 		unreachable!()
 	}
 }
 // ----
 pub struct ScrubWorker {
 	manager: Arc<BlockManager>,
 	rx_cmd: mpsc::Receiver<ScrubWorkerCommand>,
 	work: ScrubWorkerState,
 	tranquilizer: Tranquilizer,
 	persister: Persister<ScrubWorkerPersisted>,
 	persisted: ScrubWorkerPersisted,
 }
 #[derive(Serialize, Deserialize)]
 struct ScrubWorkerPersisted {
 	tranquility: u32,
 	time_last_complete_scrub: u64,
 	corruptions_detected: u64,
 }
 enum ScrubWorkerState {
 	Running(BlockStoreIterator),
 	Paused(BlockStoreIterator, u64), // u64 = time when to resume scrub
 	Finished,
 }
 impl Default for ScrubWorkerState {
 	fn default() -> Self {
 		ScrubWorkerState::Finished
 	}
 }
 #[derive(Debug)]
 pub enum ScrubWorkerCommand {
 	Start,
 	Pause(Duration),
 	Resume,
 	Cancel,
 	SetTranquility(u32),
 }
 impl ScrubWorker {
 	pub fn new(manager: Arc<BlockManager>, rx_cmd: mpsc::Receiver<ScrubWorkerCommand>) -> Self {
 		let persister = Persister::new(&manager.system.metadata_dir, "scrub_info");
 		let persisted = match persister.load() {
 			Ok(v) => v,
 			Err(_) => ScrubWorkerPersisted {
 				time_last_complete_scrub: 0,
 				tranquility: 4,
 				corruptions_detected: 0,
 			},
 		};
 		Self {
 			manager,
 			rx_cmd,
 			work: ScrubWorkerState::Finished,
 			tranquilizer: Tranquilizer::new(30),
 			persister,
 			persisted,
 		}
 	}
 	async fn handle_cmd(&mut self, cmd: ScrubWorkerCommand) {
 		match cmd {
 			ScrubWorkerCommand::Start => {
 				self.work = match std::mem::take(&mut self.work) {
 					ScrubWorkerState::Finished => {
 						let iterator = BlockStoreIterator::new(&self.manager);
 						ScrubWorkerState::Running(iterator)
 					}
 					work => {
 						error!("Cannot start scrub worker: already running!");
 						work
 					}
 				};
 			}
 			ScrubWorkerCommand::Pause(dur) => {
 				self.work = match std::mem::take(&mut self.work) {
 					ScrubWorkerState::Running(it) | ScrubWorkerState::Paused(it, _) => {
 						ScrubWorkerState::Paused(it, now_msec() + dur.as_millis() as u64)
 					}
 					work => {
 						error!("Cannot pause scrub worker: not running!");
 						work
 					}
 				};
 			}
 			ScrubWorkerCommand::Resume => {
 				self.work = match std::mem::take(&mut self.work) {
 					ScrubWorkerState::Paused(it, _) => ScrubWorkerState::Running(it),
 					work => {
 						error!("Cannot resume scrub worker: not paused!");
 						work
 					}
 				};
 			}
 			ScrubWorkerCommand::Cancel => {
 				self.work = match std::mem::take(&mut self.work) {
 					ScrubWorkerState::Running(_) | ScrubWorkerState::Paused(_, _) => {
 						ScrubWorkerState::Finished
 					}
 					work => {
 						error!("Cannot cancel scrub worker: not running!");
 						work
 					}
 				}
 			}
 			ScrubWorkerCommand::SetTranquility(t) => {
 				self.persisted.tranquility = t;
 				if let Err(e) = self.persister.save_async(&self.persisted).await {
 					error!("Could not save new tranquilitiy value: {}", e);
 				}
 			}
 		}
 	}
 }
 #[async_trait]
 impl Worker for ScrubWorker {
 	fn name(&self) -> String {
 		"Block scrub worker".into()
 	}
 	fn info(&self) -> Option<String> {
 		let s = match &self.work {
 			ScrubWorkerState::Running(bsi) => format!(
 				"{:.2}% done (tranquility = {})",
 				bsi.progress() * 100.,
 				self.persisted.tranquility
 			),
 			ScrubWorkerState::Paused(bsi, rt) => {
 				format!(
 					"Paused, {:.2}% done, resumes at {}",
 					bsi.progress() * 100.,
 					msec_to_rfc3339(*rt)
 				)
 			}
 			ScrubWorkerState::Finished => format!(
 				"Last completed scrub: {}",
 				msec_to_rfc3339(self.persisted.time_last_complete_scrub)
 			),
 		};
 		Some(format!(
 			"{} ; corruptions detected: {}",
 			s, self.persisted.corruptions_detected
 		))
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		match self.rx_cmd.try_recv() {
 			Ok(cmd) => self.handle_cmd(cmd).await,
 			Err(mpsc::error::TryRecvError::Disconnected) => return Ok(WorkerState::Done),
 			Err(mpsc::error::TryRecvError::Empty) => (),
 		};
 		match &mut self.work {
 			ScrubWorkerState::Running(bsi) => {
 				self.tranquilizer.reset();
 				if let Some(hash) = bsi.next().await? {
 					match self.manager.read_block(&hash).await {
 						Err(Error::CorruptData(_)) => {
 							error!("Found corrupt data block during scrub: {:?}", hash);
 							self.persisted.corruptions_detected += 1;
 							self.persister.save_async(&self.persisted).await?;
 						}
 						Err(e) => return Err(e),
 						_ => (),
 					};
 					Ok(self
 						.tranquilizer
 						.tranquilize_worker(self.persisted.tranquility))
 				} else {
 					self.persisted.time_last_complete_scrub = now_msec();
 					self.persister.save_async(&self.persisted).await?;
 					self.work = ScrubWorkerState::Finished;
 					self.tranquilizer.clear();
 					Ok(WorkerState::Idle)
 				}
 			}
 			_ => Ok(WorkerState::Idle),
 		}
 	}
 	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
 		let (wait_until, command) = match &self.work {
 			ScrubWorkerState::Running(_) => return WorkerState::Busy,
 			ScrubWorkerState::Paused(_, resume_time) => (*resume_time, ScrubWorkerCommand::Resume),
 			ScrubWorkerState::Finished => (
 				self.persisted.time_last_complete_scrub + SCRUB_INTERVAL.as_millis() as u64,
 				ScrubWorkerCommand::Start,
 			),
 		};
 		let now = now_msec();
 		if now >= wait_until {
 			self.handle_cmd(command).await;
 			return WorkerState::Busy;
 		}
 		let delay = Duration::from_millis(wait_until - now);
 		select! {
 			_ = tokio::time::sleep(delay) => self.handle_cmd(command).await,
 			cmd = self.rx_cmd.recv() => if let Some(cmd) = cmd {
 				self.handle_cmd(cmd).await;
 			} else {
 				return WorkerState::Done;
 			}
 		}
 		match &self.work {
 			ScrubWorkerState::Running(_) => WorkerState::Busy,
 			_ => WorkerState::Idle,
 		}
 	}
 }
 // ----
 struct BlockStoreIterator {
 	path: Vec<ReadingDir>,
 }
 enum ReadingDir {
 	Pending(PathBuf),
 	Read {
 		subpaths: Vec<fs::DirEntry>,
 		pos: usize,
 	},
 }
 impl BlockStoreIterator {
 	fn new(manager: &BlockManager) -> Self {
 		let root_dir = manager.data_dir.clone();
 		Self {
 			path: vec![ReadingDir::Pending(root_dir)],
 		}
 	}
 	/// Returns progress done, between 0 and 1
 	fn progress(&self) -> f32 {
 		if self.path.is_empty() {
 			1.0
 		} else {
 			let mut ret = 0.0;
 			let mut next_div = 1;
 			for p in self.path.iter() {
 				match p {
 					ReadingDir::Pending(_) => break,
 					ReadingDir::Read { subpaths, pos } => {
 						next_div *= subpaths.len();
 						ret += ((*pos - 1) as f32) / (next_div as f32);
 					}
 				}
 			}
 			ret
 		}
 	}
 	async fn next(&mut self) -> Result<Option<Hash>, Error> {
 		loop {
 			let last_path = match self.path.last_mut() {
 				None => return Ok(None),
 				Some(lp) => lp,
 			};
 			if let ReadingDir::Pending(path) = last_path {
 				let mut reader = fs::read_dir(&path).await?;
 				let mut subpaths = vec![];
 				while let Some(ent) = reader.next_entry().await? {
 					subpaths.push(ent);
 				}
 				*last_path = ReadingDir::Read { subpaths, pos: 0 };
 			}
 			let (subpaths, pos) = match *last_path {
 				ReadingDir::Read {
 					ref subpaths,
 					ref mut pos,
 				} => (subpaths, pos),
 				ReadingDir::Pending(_) => unreachable!(),
 			};
 			let data_dir_ent = match subpaths.get(*pos) {
 				None => {
 					self.path.pop();
 					continue;
 				}
 				Some(ent) => {
 					*pos += 1;
 					ent
 				}
 			};
 			let name = data_dir_ent.file_name();
 			let name = if let Ok(n) = name.into_string() {
 				n
 			} else {
 				continue;
 			};
 			let ent_type = data_dir_ent.file_type().await?;
 			let name = name.strip_suffix(".zst").unwrap_or(&name);
 			if name.len() == 2 && hex::decode(&name).is_ok() && ent_type.is_dir() {
 				let path = data_dir_ent.path();
 				self.path.push(ReadingDir::Pending(path));
 			} else if name.len() == 64 {
 				if let Ok(h) = hex::decode(&name) {
 					let mut hash = [0u8; 32];
 					hash.copy_from_slice(&h);
 					return Ok(Some(hash.into()));
 				}
 			}
 		}
 	}
 }
--- a/src/db/Cargo.toml
+++ b/src/db/Cargo.toml
@ -19,7 +19,7 @@ required-features = ["cli"]
 [dependencies]
 err-derive = "0.3"
 hexdump = "0.1"
-log = "0.4"
+tracing = "0.1.30"
 heed = "0.11"
 rusqlite = { version = "0.27", features = ["bundled"] }
--- a/src/db/sqlite_adapter.rs
+++ b/src/db/sqlite_adapter.rs
@ -6,7 +6,7 @@ use std::pin::Pin;
 use std::ptr::NonNull;
 use std::sync::{Arc, Mutex, MutexGuard};
-use log::trace;
+use tracing::trace;
 use rusqlite::{params, Connection, Rows, Statement, Transaction};
--- a/src/garage/Cargo.toml
+++ b/src/garage/Cargo.toml
@ -23,6 +23,7 @@ path = "tests/lib.rs"
 [dependencies]
 garage_db = { version = "0.8.0", path = "../db" }
 garage_api = { version = "0.7.0", path = "../api" }
 garage_block = { version = "0.7.0", path = "../block" }
 garage_model = { version = "0.7.0", path = "../model" }
 garage_rpc = { version = "0.7.0", path = "../rpc" }
 garage_table = { version = "0.7.0", path = "../table" }
@ -31,6 +32,7 @@ garage_web = { version = "0.7.0", path = "../web" }
 bytes = "1.0"
 bytesize = "1.1"
 timeago = "0.3"
 hex = "0.4"
 tracing = { version = "0.1.30", features = ["log-always"] }
 pretty_env_logger = "0.4"
--- a/src/garage/admin.rs
+++ b/src/garage/admin.rs
@ -24,7 +24,7 @@ use garage_model::migrate::Migrate;
 use garage_model::permission::*;
 use crate::cli::*;
-use crate::repair::online::OnlineRepair;
+use crate::repair::online::launch_online_repair;
 pub const ADMIN_RPC_PATH: &str = "garage/admin_rpc.rs/Rpc";
@ -36,6 +36,7 @@ pub enum AdminRpc {
 	LaunchRepair(RepairOpt),
 	Migrate(MigrateOpt),
 	Stats(StatsOpt),
 	Worker(WorkerOpt),
 	// Replies
 	Ok(String),
@ -47,6 +48,10 @@ pub enum AdminRpc {
 	},
 	KeyList(Vec<(String, String)>),
 	KeyInfo(Key, HashMap<Uuid, Bucket>),
 	WorkerList(
 		HashMap<usize, garage_util::background::WorkerInfo>,
 		WorkerListOpt,
 	),
 }
 impl Rpc for AdminRpc {
@ -693,15 +698,7 @@ impl AdminRpcHandler {
 				)))
 			}
 		} else {
-			let repair = OnlineRepair {
+			launch_online_repair(self.garage.clone(), opt).await;
 				garage: self.garage.clone(),
 			};
 			self.garage
 				.system
 				.background
 				.spawn_worker("Repair worker".into(), move |must_exit| async move {
 					repair.repair_worker(opt, must_exit).await
 				});
 			Ok(AdminRpc::Ok(format!(
 				"Repair launched on {:?}",
 				self.garage.system.id
@ -830,6 +827,17 @@ impl AdminRpcHandler {
 		Ok(())
 	}
 	// ----
 	async fn handle_worker_cmd(&self, opt: WorkerOpt) -> Result<AdminRpc, Error> {
 		match opt.cmd {
 			WorkerCmd::List { opt } => {
 				let workers = self.garage.background.get_worker_info();
 				Ok(AdminRpc::WorkerList(workers, opt))
 			}
 		}
 	}
 }
 #[async_trait]
@ -845,6 +853,7 @@ impl EndpointHandler<AdminRpc> for AdminRpcHandler {
 			AdminRpc::Migrate(opt) => self.handle_migrate(opt.clone()).await,
 			AdminRpc::LaunchRepair(opt) => self.handle_launch_repair(opt.clone()).await,
 			AdminRpc::Stats(opt) => self.handle_stats(opt.clone()).await,
 			AdminRpc::Worker(opt) => self.handle_worker_cmd(opt.clone()).await,
 			m => Err(GarageError::unexpected_rpc_message(m).into()),
 		}
 	}
--- a/src/garage/cli/cmd.rs
+++ b/src/garage/cli/cmd.rs
@ -1,4 +1,5 @@
 use std::collections::HashSet;
 use std::time::Duration;
 use garage_util::error::*;
 use garage_util::formater::format_table;
@ -39,6 +40,7 @@ pub async fn cli_command_dispatch(
 			cmd_admin(admin_rpc_endpoint, rpc_host, AdminRpc::LaunchRepair(ro)).await
 		}
 		Command::Stats(so) => cmd_admin(admin_rpc_endpoint, rpc_host, AdminRpc::Stats(so)).await,
 		Command::Worker(wo) => cmd_admin(admin_rpc_endpoint, rpc_host, AdminRpc::Worker(wo)).await,
 		_ => unreachable!(),
 	}
 }
@ -100,6 +102,7 @@ pub async fn cmd_status(rpc_cli: &Endpoint<SystemRpc, ()>, rpc_host: NodeID) ->
 			vec!["ID\tHostname\tAddress\tTags\tZone\tCapacity\tLast seen".to_string()];
 		for adv in status.iter().filter(|adv| !adv.is_up) {
 			if let Some(NodeRoleV(Some(cfg))) = layout.roles.get(&adv.id) {
 				let tf = timeago::Formatter::new();
 				failed_nodes.push(format!(
 					"{id:?}\t{host}\t{addr}\t[{tags}]\t{zone}\t{capacity}\t{last_seen}",
 					id = adv.id,
@ -110,7 +113,7 @@ pub async fn cmd_status(rpc_cli: &Endpoint<SystemRpc, ()>, rpc_host: NodeID) ->
 					capacity = cfg.capacity_string(),
 					last_seen = adv
 						.last_seen_secs_ago
-						.map(|s| format!("{}s ago", s))
+						.map(|s| tf.convert(Duration::from_secs(s)))
 						.unwrap_or_else(|| "never seen".into()),
 				));
 			}
@ -182,6 +185,9 @@ pub async fn cmd_admin(
 		AdminRpc::KeyInfo(key, rb) => {
 			print_key_info(&key, &rb);
 		}
 		AdminRpc::WorkerList(wi, wlo) => {
 			print_worker_info(wi, wlo);
 		}
 		r => {
 			error!("Unexpected response: {:?}", r);
 		}
--- a/src/garage/cli/structs.rs
+++ b/src/garage/cli/structs.rs
@ -45,6 +45,10 @@ pub enum Command {
 	/// Gather node statistics
 	#[structopt(name = "stats")]
 	Stats(StatsOpt),
 	/// Manage background workers
 	#[structopt(name = "worker")]
 	Worker(WorkerOpt),
 }
 #[derive(StructOpt, Debug)]
@ -423,8 +427,29 @@ pub enum RepairWhat {
 	/// Verify integrity of all blocks on disc (extremely slow, i/o intensive)
 	#[structopt(name = "scrub")]
 	Scrub {
-		/// Tranquility factor (see tranquilizer documentation)
+		#[structopt(subcommand)]
-		#[structopt(name = "tranquility", default_value = "2")]
+		cmd: ScrubCmd,
 	},
 }
 #[derive(Serialize, Deserialize, StructOpt, Debug, Eq, PartialEq, Clone)]
 pub enum ScrubCmd {
 	/// Start scrub
 	#[structopt(name = "start")]
 	Start,
 	/// Pause scrub (it will resume automatically after 24 hours)
 	#[structopt(name = "pause")]
 	Pause,
 	/// Resume paused scrub
 	#[structopt(name = "resume")]
 	Resume,
 	/// Cancel scrub in progress
 	#[structopt(name = "cancel")]
 	Cancel,
 	/// Set tranquility level for in-progress and future scrubs
 	#[structopt(name = "set-tranquility")]
 	SetTranquility {
 		#[structopt()]
 		tranquility: u32,
 	},
 }
@ -460,3 +485,29 @@ pub struct StatsOpt {
 	#[structopt(short = "d", long = "detailed")]
 	pub detailed: bool,
 }
 #[derive(Serialize, Deserialize, StructOpt, Debug, Clone)]
 pub struct WorkerOpt {
 	#[structopt(subcommand)]
 	pub cmd: WorkerCmd,
 }
 #[derive(Serialize, Deserialize, StructOpt, Debug, Eq, PartialEq, Clone)]
 pub enum WorkerCmd {
 	/// List all workers on Garage node
 	#[structopt(name = "list")]
 	List {
 		#[structopt(flatten)]
 		opt: WorkerListOpt,
 	},
 }
 #[derive(Serialize, Deserialize, StructOpt, Debug, Eq, PartialEq, Clone, Copy)]
 pub struct WorkerListOpt {
 	/// Show only busy workers
 	#[structopt(short = "b", long = "busy")]
 	pub busy: bool,
 	/// Show only workers with errors
 	#[structopt(short = "e", long = "errors")]
 	pub errors: bool,
 }
--- a/src/garage/cli/util.rs
+++ b/src/garage/cli/util.rs
@ -1,14 +1,19 @@
 use std::collections::HashMap;
 use std::time::Duration;
 use garage_util::background::*;
 use garage_util::crdt::*;
 use garage_util::data::Uuid;
 use garage_util::error::*;
 use garage_util::formater::format_table;
 use garage_util::time::*;
 use garage_model::bucket_table::*;
 use garage_model::key_table::*;
 use garage_model::s3::object_table::{BYTES, OBJECTS, UNFINISHED_UPLOADS};
 use crate::cli::structs::WorkerListOpt;
 pub fn print_bucket_list(bl: Vec<Bucket>) {
 	println!("List of buckets:");
@ -235,3 +240,56 @@ pub fn find_matching_node(
 		Ok(candidates[0])
 	}
 }
 pub fn print_worker_info(wi: HashMap<usize, WorkerInfo>, wlo: WorkerListOpt) {
 	let mut wi = wi.into_iter().collect::<Vec<_>>();
 	wi.sort_by_key(|(tid, info)| {
 		(
 			match info.state {
 				WorkerState::Busy | WorkerState::Throttled(_) => 0,
 				WorkerState::Idle => 1,
 				WorkerState::Done => 2,
 			},
 			*tid,
 		)
 	});
 	let mut table = vec![];
 	for (tid, info) in wi.iter() {
 		if wlo.busy && !matches!(info.state, WorkerState::Busy | WorkerState::Throttled(_)) {
 			continue;
 		}
 		if wlo.errors && info.errors == 0 {
 			continue;
 		}
 		table.push(format!("{}\t{}\t{}", tid, info.state, info.name));
 		if let Some(i) = &info.info {
 			table.push(format!("\t\t  {}", i));
 		}
 		let tf = timeago::Formatter::new();
 		let (err_ago, err_msg) = info
 			.last_error
 			.as_ref()
 			.map(|(m, t)| {
 				(
 					tf.convert(Duration::from_millis(now_msec() - t)),
 					m.as_str(),
 				)
 			})
 			.unwrap_or(("(?) ago".into(), "(?)"));
 		if info.consecutive_errors > 0 {
 			table.push(format!(
 				"\t\t  {} consecutive errors ({} total), last {}",
 				info.consecutive_errors, info.errors, err_ago,
 			));
 			table.push(format!("\t\t  {}", err_msg));
 		} else if info.errors > 0 {
 			table.push(format!("\t\t  ({} errors, last {})", info.errors, err_ago,));
 			if wlo.errors {
 				table.push(format!("\t\t  {}", err_msg));
 			}
 		}
 	}
 	format_table(table);
 }
--- a/src/garage/repair/online.rs
+++ b/src/garage/repair/online.rs
@ -1,89 +1,110 @@
 use std::sync::Arc;
 use std::time::Duration;
 use async_trait::async_trait;
 use tokio::sync::watch;
 use garage_block::repair::ScrubWorkerCommand;
 use garage_model::garage::Garage;
 use garage_model::s3::block_ref_table::*;
 use garage_model::s3::object_table::*;
 use garage_model::s3::version_table::*;
 use garage_table::*;
 use garage_util::background::*;
 use garage_util::error::Error;
 use crate::*;
-pub struct OnlineRepair {
+pub async fn launch_online_repair(garage: Arc<Garage>, opt: RepairOpt) {
-	pub garage: Arc<Garage>,
+	match opt.what {
 		RepairWhat::Tables => {
 			info!("Launching a full sync of tables");
 			garage.bucket_table.syncer.add_full_sync();
 			garage.object_table.syncer.add_full_sync();
 			garage.version_table.syncer.add_full_sync();
 			garage.block_ref_table.syncer.add_full_sync();
 			garage.key_table.syncer.add_full_sync();
 		}
 		RepairWhat::Versions => {
 			info!("Repairing the versions table");
 			garage
 				.background
 				.spawn_worker(RepairVersionsWorker::new(garage.clone()));
 		}
 		RepairWhat::BlockRefs => {
 			info!("Repairing the block refs table");
 			garage
 				.background
 				.spawn_worker(RepairBlockrefsWorker::new(garage.clone()));
 		}
 		RepairWhat::Blocks => {
 			info!("Repairing the stored blocks");
 			garage
 				.background
 				.spawn_worker(garage_block::repair::RepairWorker::new(
 					garage.block_manager.clone(),
 				));
 		}
 		RepairWhat::Scrub { cmd } => {
 			let cmd = match cmd {
 				ScrubCmd::Start => ScrubWorkerCommand::Start,
 				ScrubCmd::Pause => ScrubWorkerCommand::Pause(Duration::from_secs(3600 * 24)),
 				ScrubCmd::Resume => ScrubWorkerCommand::Resume,
 				ScrubCmd::Cancel => ScrubWorkerCommand::Cancel,
 				ScrubCmd::SetTranquility { tranquility } => {
 					ScrubWorkerCommand::SetTranquility(tranquility)
 				}
 			};
 			info!("Sending command to scrub worker: {:?}", cmd);
 			garage.block_manager.send_scrub_command(cmd).await;
 		}
 	}
 }
-impl OnlineRepair {
+// ----
-	pub async fn repair_worker(&self, opt: RepairOpt, must_exit: watch::Receiver<bool>) {
+
-		if let Err(e) = self.repair_worker_aux(opt, must_exit).await {
+struct RepairVersionsWorker {
-			warn!("Repair worker failed with error: {}", e);
+	garage: Arc<Garage>,
 	pos: Vec<u8>,
 	counter: usize,
 }
 impl RepairVersionsWorker {
 	fn new(garage: Arc<Garage>) -> Self {
 		Self {
 			garage,
 			pos: vec![],
 			counter: 0,
 		}
 	}
 }
-	async fn repair_worker_aux(
+#[async_trait]
-		&self,
+impl Worker for RepairVersionsWorker {
-		opt: RepairOpt,
+	fn name(&self) -> String {
-		must_exit: watch::Receiver<bool>,
+		"Version repair worker".into()
 	) -> Result<(), Error> {
 		match opt.what {
 			RepairWhat::Tables => {
 				info!("Launching a full sync of tables");
 				self.garage.bucket_table.syncer.add_full_sync();
 				self.garage.object_table.syncer.add_full_sync();
 				self.garage.version_table.syncer.add_full_sync();
 				self.garage.block_ref_table.syncer.add_full_sync();
 				self.garage.key_table.syncer.add_full_sync();
 			}
 			RepairWhat::Versions => {
 				info!("Repairing the versions table");
 				self.repair_versions(&must_exit).await?;
 			}
 			RepairWhat::BlockRefs => {
 				info!("Repairing the block refs table");
 				self.repair_block_ref(&must_exit).await?;
 			}
 			RepairWhat::Blocks => {
 				info!("Repairing the stored blocks");
 				self.garage
 					.block_manager
 					.repair_data_store(&must_exit)
 					.await?;
 			}
 			RepairWhat::Scrub { tranquility } => {
 				info!("Verifying integrity of stored blocks");
 				self.garage
 					.block_manager
 					.scrub_data_store(&must_exit, tranquility)
 					.await?;
 			}
 		}
 		Ok(())
 	}
-	async fn repair_versions(&self, must_exit: &watch::Receiver<bool>) -> Result<(), Error> {
+	fn info(&self) -> Option<String> {
-		let mut pos = vec![];
+		Some(format!("{} items done", self.counter))
-		let mut i = 0;
+	}
-		while !*must_exit.borrow() {
+	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
-			let item_bytes = match self.garage.version_table.data.store.get_gt(pos)? {
+		let item_bytes = match self.garage.version_table.data.store.get_gt(&self.pos)? {
-				Some((k, v)) => {
+			Some((k, v)) => {
-					pos = k;
+				self.pos = k;
-					v
+				v
 				}
 				None => break,
 			};
 			i += 1;
 			if i % 1000 == 0 {
 				info!("repair_versions: {}", i);
 			}
-
+			None => {
-			let version = rmp_serde::decode::from_read_ref::<_, Version>(&item_bytes)?;
+				info!("repair_versions: finished, done {}", self.counter);
-			if version.deleted.get() {
+				return Ok(WorkerState::Done);
 				continue;
 			}
 		};
 		self.counter += 1;
 		let version = rmp_serde::decode::from_read_ref::<_, Version>(&item_bytes)?;
 		if !version.deleted.get() {
 			let object = self
 				.garage
 				.object_table
@ -109,32 +130,59 @@ impl OnlineRepair {
 					.await?;
 			}
 		}
-		info!("repair_versions: finished, done {}", i);
+
-		Ok(())
+		Ok(WorkerState::Busy)
 	}
-	async fn repair_block_ref(&self, must_exit: &watch::Receiver<bool>) -> Result<(), Error> {
+	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
-		let mut pos = vec![];
+		unreachable!()
-		let mut i = 0;
+	}
 }
-		while !*must_exit.borrow() {
+// ----
 			let item_bytes = match self.garage.block_ref_table.data.store.get_gt(pos)? {
 				Some((k, v)) => {
 					pos = k;
 					v
 				}
 				None => break,
 			};
-			i += 1;
+struct RepairBlockrefsWorker {
-			if i % 1000 == 0 {
+	garage: Arc<Garage>,
-				info!("repair_block_ref: {}", i);
+	pos: Vec<u8>,
 	counter: usize,
 }
 impl RepairBlockrefsWorker {
 	fn new(garage: Arc<Garage>) -> Self {
 		Self {
 			garage,
 			pos: vec![],
 			counter: 0,
 		}
 	}
 }
 #[async_trait]
 impl Worker for RepairBlockrefsWorker {
 	fn name(&self) -> String {
 		"Block refs repair worker".into()
 	}
 	fn info(&self) -> Option<String> {
 		Some(format!("{} items done", self.counter))
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		let item_bytes = match self.garage.block_ref_table.data.store.get_gt(&self.pos)? {
 			Some((k, v)) => {
 				self.pos = k;
 				v
 			}
-
+			None => {
-			let block_ref = rmp_serde::decode::from_read_ref::<_, BlockRef>(&item_bytes)?;
+				info!("repair_block_ref: finished, done {}", self.counter);
-			if block_ref.deleted.get() {
+				return Ok(WorkerState::Done);
 				continue;
 			}
 		};
 		self.counter += 1;
 		let block_ref = rmp_serde::decode::from_read_ref::<_, BlockRef>(&item_bytes)?;
 		if !block_ref.deleted.get() {
 			let version = self
 				.garage
 				.version_table
@ -157,7 +205,11 @@ impl OnlineRepair {
 					.await?;
 			}
 		}
-		info!("repair_block_ref: finished, done {}", i);
+
-		Ok(())
+		Ok(WorkerState::Busy)
 	}
 	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
 		unreachable!()
 	}
 }
--- a/src/model/index_counter.rs
+++ b/src/model/index_counter.rs
@ -2,8 +2,8 @@ use core::ops::Bound;
 use std::collections::{hash_map, BTreeMap, HashMap};
 use std::marker::PhantomData;
 use std::sync::Arc;
 use std::time::Duration;
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 use tokio::sync::{mpsc, watch};
@ -11,6 +11,7 @@ use garage_db as db;
 use garage_rpc::ring::Ring;
 use garage_rpc::system::System;
 use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::time::*;
@ -171,11 +172,13 @@ impl<T: CountedItem> IndexCounter<T> {
 			),
 		});
-		let this2 = this.clone();
+		background.spawn_worker(IndexPropagatorWorker {
-		background.spawn_worker(
+			index_counter: this.clone(),
-			format!("{} index counter propagator", T::COUNTER_TABLE_NAME),
+			propagate_rx,
-			move |must_exit| this2.clone().propagate_loop(propagate_rx, must_exit),
+			buf: HashMap::new(),
-		);
+			errors: 0,
 		});
 		this
 	}
@ -239,68 +242,6 @@ impl<T: CountedItem> IndexCounter<T> {
 		Ok(())
 	}
 	async fn propagate_loop(
 		self: Arc<Self>,
 		mut propagate_rx: mpsc::UnboundedReceiver<(T::CP, T::CS, LocalCounterEntry<T>)>,
 		must_exit: watch::Receiver<bool>,
 	) {
 		// This loop batches updates to counters to be sent all at once.
 		// They are sent once the propagate_rx channel has been emptied (or is closed).
 		let mut buf = HashMap::new();
 		let mut errors = 0;
 		loop {
 			let (ent, closed) = match propagate_rx.try_recv() {
 				Ok(ent) => (Some(ent), false),
 				Err(mpsc::error::TryRecvError::Empty) if buf.is_empty() => {
 					match propagate_rx.recv().await {
 						Some(ent) => (Some(ent), false),
 						None => (None, true),
 					}
 				}
 				Err(mpsc::error::TryRecvError::Empty) => (None, false),
 				Err(mpsc::error::TryRecvError::Disconnected) => (None, true),
 			};
 			if let Some((pk, sk, counters)) = ent {
 				let tree_key = self.table.data.tree_key(&pk, &sk);
 				let dist_entry = counters.into_counter_entry(self.this_node);
 				match buf.entry(tree_key) {
 					hash_map::Entry::Vacant(e) => {
 						e.insert(dist_entry);
 					}
 					hash_map::Entry::Occupied(mut e) => {
 						e.get_mut().merge(&dist_entry);
 					}
 				}
 				// As long as we can add entries, loop back and add them to batch
 				// before sending batch to other nodes
 				continue;
 			}
 			if !buf.is_empty() {
 				let entries = buf.iter().map(|(_k, v)| v);
 				if let Err(e) = self.table.insert_many(entries).await {
 					errors += 1;
 					if errors >= 2 && *must_exit.borrow() {
 						error!("({}) Could not propagate {} counter values: {}, these counters will not be updated correctly.", T::COUNTER_TABLE_NAME, buf.len(), e);
 						break;
 					}
 					warn!("({}) Could not propagate {} counter values: {}, retrying in 5 seconds (retry #{})", T::COUNTER_TABLE_NAME, buf.len(), e, errors);
 					tokio::time::sleep(Duration::from_secs(5)).await;
 					continue;
 				}
 				buf.clear();
 				errors = 0;
 			}
 			if closed || *must_exit.borrow() {
 				break;
 			}
 		}
 	}
 	pub fn offline_recount_all<TS, TR>(
 		&self,
 		counted_table: &Arc<Table<TS, TR>>,
@ -437,6 +378,98 @@ impl<T: CountedItem> IndexCounter<T> {
 	}
 }
 struct IndexPropagatorWorker<T: CountedItem> {
 	index_counter: Arc<IndexCounter<T>>,
 	propagate_rx: mpsc::UnboundedReceiver<(T::CP, T::CS, LocalCounterEntry<T>)>,
 	buf: HashMap<Vec<u8>, CounterEntry<T>>,
 	errors: usize,
 }
 impl<T: CountedItem> IndexPropagatorWorker<T> {
 	fn add_ent(&mut self, pk: T::CP, sk: T::CS, counters: LocalCounterEntry<T>) {
 		let tree_key = self.index_counter.table.data.tree_key(&pk, &sk);
 		let dist_entry = counters.into_counter_entry(self.index_counter.this_node);
 		match self.buf.entry(tree_key) {
 			hash_map::Entry::Vacant(e) => {
 				e.insert(dist_entry);
 			}
 			hash_map::Entry::Occupied(mut e) => {
 				e.get_mut().merge(&dist_entry);
 			}
 		}
 	}
 }
 #[async_trait]
 impl<T: CountedItem> Worker for IndexPropagatorWorker<T> {
 	fn name(&self) -> String {
 		format!("{} index counter propagator", T::COUNTER_TABLE_NAME)
 	}
 	fn info(&self) -> Option<String> {
 		if !self.buf.is_empty() {
 			Some(format!("{} items in queue", self.buf.len()))
 		} else {
 			None
 		}
 	}
 	async fn work(&mut self, must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		// This loop batches updates to counters to be sent all at once.
 		// They are sent once the propagate_rx channel has been emptied (or is closed).
 		let closed = loop {
 			match self.propagate_rx.try_recv() {
 				Ok((pk, sk, counters)) => {
 					self.add_ent(pk, sk, counters);
 				}
 				Err(mpsc::error::TryRecvError::Empty) => break false,
 				Err(mpsc::error::TryRecvError::Disconnected) => break true,
 			}
 		};
 		if !self.buf.is_empty() {
 			let entries_k = self.buf.keys().take(100).cloned().collect::<Vec<_>>();
 			let entries = entries_k.iter().map(|k| self.buf.get(k).unwrap());
 			if let Err(e) = self.index_counter.table.insert_many(entries).await {
 				self.errors += 1;
 				if self.errors >= 2 && *must_exit.borrow() {
 					error!("({}) Could not propagate {} counter values: {}, these counters will not be updated correctly.", T::COUNTER_TABLE_NAME, self.buf.len(), e);
 					return Ok(WorkerState::Done);
 				}
 				// Propagate error up to worker manager, it will log it, increment a counter,
 				// and sleep for a certain delay (with exponential backoff), waiting for
 				// things to go back to normal
 				return Err(e);
 			} else {
 				for k in entries_k {
 					self.buf.remove(&k);
 				}
 				self.errors = 0;
 			}
 			return Ok(WorkerState::Busy);
 		} else if closed {
 			return Ok(WorkerState::Done);
 		} else {
 			return Ok(WorkerState::Idle);
 		}
 	}
 	async fn wait_for_work(&mut self, _must_exit: &watch::Receiver<bool>) -> WorkerState {
 		match self.propagate_rx.recv().await {
 			Some((pk, sk, counters)) => {
 				self.add_ent(pk, sk, counters);
 				WorkerState::Busy
 			}
 			None => match self.buf.is_empty() {
 				false => WorkerState::Busy,
 				true => WorkerState::Done,
 			},
 		}
 	}
 }
 #[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
 struct LocalCounterEntry<T: CountedItem> {
 	pk: T::CP,
--- a/src/rpc/system.rs
+++ b/src/rpc/system.rs
@ -2,7 +2,7 @@
 use std::collections::HashMap;
 use std::io::{Read, Write};
 use std::net::{IpAddr, SocketAddr};
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::sync::{Arc, RwLock};
 use std::time::{Duration, Instant};
@ -104,6 +104,9 @@ pub struct System {
 	/// The job runner of this node
 	pub background: Arc<BackgroundRunner>,
 	/// Path to metadata directory
 	pub metadata_dir: PathBuf,
 }
 #[derive(Debug, Clone, Serialize, Deserialize)]
@ -295,6 +298,7 @@ impl System {
 			ring,
 			update_ring: Mutex::new(update_ring),
 			background,
 			metadata_dir: config.metadata_dir.clone(),
 		});
 		sys.system_endpoint.set_handler(sys.clone());
 		sys
--- a/src/table/gc.rs
+++ b/src/table/gc.rs
@ -8,12 +8,11 @@ use serde::{Deserialize, Serialize};
 use serde_bytes::ByteBuf;
 use futures::future::join_all;
 use futures::select;
 use futures_util::future::*;
 use tokio::sync::watch;
 use garage_db::counted_tree_hack::CountedTree;
 use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::time::*;
@ -69,35 +68,11 @@ where
 		gc.endpoint.set_handler(gc.clone());
-		let gc1 = gc.clone();
+		system.background.spawn_worker(GcWorker::new(gc.clone()));
 		system.background.spawn_worker(
 			format!("GC loop for {}", F::TABLE_NAME),
 			move |must_exit: watch::Receiver<bool>| gc1.gc_loop(must_exit),
 		);
 		gc
 	}
 	async fn gc_loop(self: Arc<Self>, mut must_exit: watch::Receiver<bool>) {
 		while !*must_exit.borrow() {
 			match self.gc_loop_iter().await {
 				Ok(None) => {
 					// Stuff was done, loop immediately
 				}
 				Ok(Some(wait_delay)) => {
 					// Nothing was done, wait specified delay.
 					select! {
 						_ = tokio::time::sleep(wait_delay).fuse() => {},
 						_ = must_exit.changed().fuse() => {},
 					}
 				}
 				Err(e) => {
 					warn!("({}) Error doing GC: {}", F::TABLE_NAME, e);
 				}
 			}
 		}
 	}
 	async fn gc_loop_iter(&self) -> Result<Option<Duration>, Error> {
 		let now = now_msec();
@ -328,6 +303,66 @@ where
 	}
 }
 struct GcWorker<F, R>
 where
 	F: TableSchema + 'static,
 	R: TableReplication + 'static,
 {
 	gc: Arc<TableGc<F, R>>,
 	wait_delay: Duration,
 }
 impl<F, R> GcWorker<F, R>
 where
 	F: TableSchema + 'static,
 	R: TableReplication + 'static,
 {
 	fn new(gc: Arc<TableGc<F, R>>) -> Self {
 		Self {
 			gc,
 			wait_delay: Duration::from_secs(0),
 		}
 	}
 }
 #[async_trait]
 impl<F, R> Worker for GcWorker<F, R>
 where
 	F: TableSchema + 'static,
 	R: TableReplication + 'static,
 {
 	fn name(&self) -> String {
 		format!("{} GC", F::TABLE_NAME)
 	}
 	fn info(&self) -> Option<String> {
 		let l = self.gc.data.gc_todo_len().unwrap_or(0);
 		if l > 0 {
 			Some(format!("{} items in queue", l))
 		} else {
 			None
 		}
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		match self.gc.gc_loop_iter().await? {
 			None => Ok(WorkerState::Busy),
 			Some(delay) => {
 				self.wait_delay = delay;
 				Ok(WorkerState::Idle)
 			}
 		}
 	}
 	async fn wait_for_work(&mut self, must_exit: &watch::Receiver<bool>) -> WorkerState {
 		if *must_exit.borrow() {
 			return WorkerState::Done;
 		}
 		tokio::time::sleep(self.wait_delay).await;
 		WorkerState::Busy
 	}
 }
 /// An entry stored in the gc_todo Sled tree associated with the table
 /// Contains helper function for parsing, saving, and removing
 /// such entry in Sled
--- a/src/table/merkle.rs
+++ b/src/table/merkle.rs
@ -1,14 +1,13 @@
 use std::sync::Arc;
 use std::time::Duration;
-use futures::select;
+use async_trait::async_trait;
 use futures_util::future::*;
 use serde::{Deserialize, Serialize};
 use tokio::sync::watch;
 use garage_db as db;
-use garage_util::background::BackgroundRunner;
+use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::Error;
@ -78,43 +77,17 @@ where
 			empty_node_hash,
 		});
-		let ret2 = ret.clone();
+		background.spawn_worker(MerkleWorker(ret.clone()));
 		background.spawn_worker(
 			format!("Merkle tree updater for {}", F::TABLE_NAME),
 			|must_exit: watch::Receiver<bool>| ret2.updater_loop(must_exit),
 		);
 		ret
 	}
-	async fn updater_loop(self: Arc<Self>, mut must_exit: watch::Receiver<bool>) {
+	fn updater_loop_iter(&self) -> Result<WorkerState, Error> {
 		while !*must_exit.borrow() {
 			match self.updater_loop_iter() {
 				Ok(true) => (),
 				Ok(false) => {
 					select! {
 						_ = self.data.merkle_todo_notify.notified().fuse() => {},
 						_ = must_exit.changed().fuse() => {},
 					}
 				}
 				Err(e) => {
 					warn!(
 						"({}) Error while updating Merkle tree item: {}",
 						F::TABLE_NAME,
 						e
 					);
 					tokio::time::sleep(Duration::from_secs(10)).await;
 				}
 			}
 		}
 	}
 	fn updater_loop_iter(&self) -> Result<bool, Error> {
 		if let Some((key, valhash)) = self.data.merkle_todo.first()? {
 			self.update_item(&key, &valhash)?;
-			Ok(true)
+			Ok(WorkerState::Busy)
 		} else {
-			Ok(false)
+			Ok(WorkerState::Idle)
 		}
 	}
@ -325,6 +298,54 @@ where
 	}
 }
 struct MerkleWorker<F, R>(Arc<MerkleUpdater<F, R>>)
 where
 	F: TableSchema + 'static,
 	R: TableReplication + 'static;
 #[async_trait]
 impl<F, R> Worker for MerkleWorker<F, R>
 where
 	F: TableSchema + 'static,
 	R: TableReplication + 'static,
 {
 	fn name(&self) -> String {
 		format!("{} Merkle tree updater", F::TABLE_NAME)
 	}
 	fn info(&self) -> Option<String> {
 		let l = self.0.todo_len().unwrap_or(0);
 		if l > 0 {
 			Some(format!("{} items in queue", l))
 		} else {
 			None
 		}
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		let updater = self.0.clone();
 		tokio::task::spawn_blocking(move || {
 			for _i in 0..100 {
 				let s = updater.updater_loop_iter();
 				if !matches!(s, Ok(WorkerState::Busy)) {
 					return s;
 				}
 			}
 			Ok(WorkerState::Busy)
 		})
 		.await
 		.unwrap()
 	}
 	async fn wait_for_work(&mut self, must_exit: &watch::Receiver<bool>) -> WorkerState {
 		if *must_exit.borrow() {
 			return WorkerState::Done;
 		}
 		tokio::time::sleep(Duration::from_secs(10)).await;
 		WorkerState::Busy
 	}
 }
 impl MerkleNodeKey {
 	fn encode(&self) -> Vec<u8> {
 		let mut ret = Vec::with_capacity(2 + self.prefix.len());
--- a/src/table/sync.rs
+++ b/src/table/sync.rs
@ -1,17 +1,17 @@
 use std::collections::VecDeque;
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 use std::time::{Duration, Instant};
 use async_trait::async_trait;
 use futures::select;
 use futures_util::future::*;
 use futures_util::stream::*;
 use opentelemetry::KeyValue;
 use rand::Rng;
 use serde::{Deserialize, Serialize};
 use serde_bytes::ByteBuf;
 use tokio::select;
 use tokio::sync::{mpsc, watch};
 use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::Error;
@ -34,7 +34,7 @@ pub struct TableSyncer<F: TableSchema + 'static, R: TableReplication + 'static>
 	data: Arc<TableData<F, R>>,
 	merkle: Arc<MerkleUpdater<F, R>>,
-	todo: Mutex<SyncTodo>,
+	add_full_sync_tx: mpsc::UnboundedSender<()>,
 	endpoint: Arc<Endpoint<SyncRpc, Self>>,
 }
@ -52,10 +52,6 @@ impl Rpc for SyncRpc {
 	type Response = Result<SyncRpc, Error>;
 }
 struct SyncTodo {
 	todo: Vec<TodoPartition>,
 }
 #[derive(Debug, Clone)]
 struct TodoPartition {
 	partition: Partition,
@ -80,118 +76,40 @@ where
 			.netapp
 			.endpoint(format!("garage_table/sync.rs/Rpc:{}", F::TABLE_NAME));
-		let todo = SyncTodo { todo: vec![] };
+		let (add_full_sync_tx, add_full_sync_rx) = mpsc::unbounded_channel();
 		let syncer = Arc::new(Self {
 			system: system.clone(),
 			data,
 			merkle,
-			todo: Mutex::new(todo),
+			add_full_sync_tx,
 			endpoint,
 		});
 		syncer.endpoint.set_handler(syncer.clone());
-		let (busy_tx, busy_rx) = mpsc::unbounded_channel();
+		system.background.spawn_worker(SyncWorker {
-
+			syncer: syncer.clone(),
-		let s1 = syncer.clone();
+			ring_recv: system.ring.clone(),
-		system.background.spawn_worker(
+			ring: system.ring.borrow().clone(),
-			format!("table sync watcher for {}", F::TABLE_NAME),
+			add_full_sync_rx,
-			move |must_exit: watch::Receiver<bool>| s1.watcher_task(must_exit, busy_rx),
+			todo: vec![],
-		);
+			next_full_sync: Instant::now() + Duration::from_secs(20),
 		let s2 = syncer.clone();
 		system.background.spawn_worker(
 			format!("table syncer for {}", F::TABLE_NAME),
 			move |must_exit: watch::Receiver<bool>| s2.syncer_task(must_exit, busy_tx),
 		);
 		let s3 = syncer.clone();
 		tokio::spawn(async move {
 			tokio::time::sleep(Duration::from_secs(20)).await;
 			s3.add_full_sync();
 		});
 		syncer
 	}
 	async fn watcher_task(
 		self: Arc<Self>,
 		mut must_exit: watch::Receiver<bool>,
 		mut busy_rx: mpsc::UnboundedReceiver<bool>,
 	) {
 		let mut prev_ring: Arc<Ring> = self.system.ring.borrow().clone();
 		let mut ring_recv: watch::Receiver<Arc<Ring>> = self.system.ring.clone();
 		let mut nothing_to_do_since = Some(Instant::now());
 		while !*must_exit.borrow() {
 			select! {
 				_ = ring_recv.changed().fuse() => {
 					let new_ring = ring_recv.borrow();
 					if !Arc::ptr_eq(&new_ring, &prev_ring) {
 						debug!("({}) Ring changed, adding full sync to syncer todo list", F::TABLE_NAME);
 						self.add_full_sync();
 						prev_ring = new_ring.clone();
 					}
 				}
 				busy_opt = busy_rx.recv().fuse() => {
 					if let Some(busy) = busy_opt {
 						if busy {
 							nothing_to_do_since = None;
 						} else if nothing_to_do_since.is_none() {
 							nothing_to_do_since = Some(Instant::now());
 						}
 					}
 				}
 				_ = must_exit.changed().fuse() => {},
 				_ = tokio::time::sleep(Duration::from_secs(1)).fuse() => {
 					if nothing_to_do_since.map(|t| Instant::now() - t >= ANTI_ENTROPY_INTERVAL).unwrap_or(false) {
 						nothing_to_do_since = None;
 						debug!("({}) Interval passed, adding full sync to syncer todo list", F::TABLE_NAME);
 						self.add_full_sync();
 					}
 				}
 			}
 		}
 	}
 	pub fn add_full_sync(&self) {
-		self.todo
+		if self.add_full_sync_tx.send(()).is_err() {
-			.lock()
+			error!("({}) Could not add full sync", F::TABLE_NAME);
 			.unwrap()
 			.add_full_sync(&self.data, &self.system);
 	}
 	async fn syncer_task(
 		self: Arc<Self>,
 		mut must_exit: watch::Receiver<bool>,
 		busy_tx: mpsc::UnboundedSender<bool>,
 	) {
 		while !*must_exit.borrow() {
 			let task = self.todo.lock().unwrap().pop_task();
 			if let Some(partition) = task {
 				busy_tx.send(true).unwrap();
 				let res = self
 					.clone()
 					.sync_partition(&partition, &mut must_exit)
 					.await;
 				if let Err(e) = res {
 					warn!(
 						"({}) Error while syncing {:?}: {}",
 						F::TABLE_NAME,
 						partition,
 						e
 					);
 				}
 			} else {
 				busy_tx.send(false).unwrap();
 				tokio::time::sleep(Duration::from_secs(1)).await;
 			}
 		}
 	}
 	// ----
 	async fn sync_partition(
-		self: Arc<Self>,
+		self: &Arc<Self>,
 		partition: &TodoPartition,
 		must_exit: &mut watch::Receiver<bool>,
 	) -> Result<(), Error> {
@ -577,12 +495,22 @@ where
 	}
 }
-impl SyncTodo {
+// -------- Sync Worker ---------
-	fn add_full_sync<F: TableSchema, R: TableReplication>(
+
-		&mut self,
+struct SyncWorker<F: TableSchema + 'static, R: TableReplication + 'static> {
-		data: &TableData<F, R>,
+	syncer: Arc<TableSyncer<F, R>>,
-		system: &System,
+	ring_recv: watch::Receiver<Arc<Ring>>,
-	) {
+	ring: Arc<Ring>,
 	add_full_sync_rx: mpsc::UnboundedReceiver<()>,
 	todo: Vec<TodoPartition>,
 	next_full_sync: Instant,
 }
 impl<F: TableSchema + 'static, R: TableReplication + 'static> SyncWorker<F, R> {
 	fn add_full_sync(&mut self) {
 		let system = &self.syncer.system;
 		let data = &self.syncer.data;
 		let my_id = system.id;
 		self.todo.clear();
@ -623,6 +551,8 @@ impl SyncTodo {
 				retain,
 			});
 		}
 		self.next_full_sync = Instant::now() + ANTI_ENTROPY_INTERVAL;
 	}
 	fn pop_task(&mut self) -> Option<TodoPartition> {
@ -641,6 +571,62 @@ impl SyncTodo {
 	}
 }
 #[async_trait]
 impl<F: TableSchema + 'static, R: TableReplication + 'static> Worker for SyncWorker<F, R> {
 	fn name(&self) -> String {
 		format!("{} sync", F::TABLE_NAME)
 	}
 	fn info(&self) -> Option<String> {
 		let l = self.todo.len();
 		if l > 0 {
 			Some(format!("{} partitions remaining", l))
 		} else {
 			None
 		}
 	}
 	async fn work(&mut self, must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		if let Some(partition) = self.pop_task() {
 			self.syncer.sync_partition(&partition, must_exit).await?;
 			Ok(WorkerState::Busy)
 		} else {
 			Ok(WorkerState::Idle)
 		}
 	}
 	async fn wait_for_work(&mut self, must_exit: &watch::Receiver<bool>) -> WorkerState {
 		if *must_exit.borrow() {
 			return WorkerState::Done;
 		}
 		select! {
 			s = self.add_full_sync_rx.recv() => {
 				if let Some(()) = s {
 					self.add_full_sync();
 				}
 			},
 			_ = self.ring_recv.changed() => {
 				let new_ring = self.ring_recv.borrow();
 				if !Arc::ptr_eq(&new_ring, &self.ring) {
 					self.ring = new_ring.clone();
 					drop(new_ring);
 					debug!("({}) Ring changed, adding full sync to syncer todo list", F::TABLE_NAME);
 					self.add_full_sync();
 				}
 			},
 			_ = tokio::time::sleep(self.next_full_sync - Instant::now()) => {
 				self.add_full_sync();
 			}
 		}
 		match self.todo.is_empty() {
 			false => WorkerState::Busy,
 			true => WorkerState::Idle,
 		}
 	}
 }
 // ---- UTIL ----
 fn hash_of<T: Serialize>(x: &T) -> Result<Hash, Error> {
 	Ok(blake2sum(&rmp_to_vec_all_named(x)?[..]))
 }
--- a/src/util/Cargo.toml
+++ b/src/util/Cargo.toml
@ -16,6 +16,7 @@ path = "lib.rs"
 [dependencies]
 garage_db = { version = "0.8.0", path = "../db" }
 async-trait = "0.1"
 blake2 = "0.9"
 err-derive = "0.3"
 xxhash-rust = { version = "0.8", default-features = false, features = ["xxh3"] }
--- a/src/util/background.rs
+++ b/src/util/background.rs
@ -1,160 +0,0 @@
 //! Job runner for futures and async functions
 use core::future::Future;
 use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
 use futures::future::*;
 use futures::select;
 use futures::stream::FuturesUnordered;
 use futures::StreamExt;
 use tokio::sync::{mpsc, mpsc::error::TryRecvError, watch, Mutex};
 use crate::error::Error;
 type JobOutput = Result<(), Error>;
 type Job = Pin<Box<dyn Future<Output = JobOutput> + Send>>;
 /// Job runner for futures and async functions
 pub struct BackgroundRunner {
 	stop_signal: watch::Receiver<bool>,
 	queue_in: mpsc::UnboundedSender<(Job, bool)>,
 	worker_in: mpsc::UnboundedSender<tokio::task::JoinHandle<()>>,
 }
 impl BackgroundRunner {
 	/// Create a new BackgroundRunner
 	pub fn new(
 		n_runners: usize,
 		stop_signal: watch::Receiver<bool>,
 	) -> (Arc<Self>, tokio::task::JoinHandle<()>) {
 		let (worker_in, mut worker_out) = mpsc::unbounded_channel();
 		let stop_signal_2 = stop_signal.clone();
 		let await_all_done = tokio::spawn(async move {
 			let mut workers = FuturesUnordered::new();
 			let mut shutdown_timer = 0;
 			loop {
 				let closed = match worker_out.try_recv() {
 					Ok(wkr) => {
 						workers.push(wkr);
 						false
 					}
 					Err(TryRecvError::Empty) => false,
 					Err(TryRecvError::Disconnected) => true,
 				};
 				select! {
 					res = workers.next() => {
 						if let Some(Err(e)) = res {
 							error!("Worker exited with error: {}", e);
 						}
 					}
 					_ = tokio::time::sleep(Duration::from_secs(1)).fuse() => {
 						if closed || *stop_signal_2.borrow() {
 							shutdown_timer += 1;
 							if shutdown_timer >= 10 {
 								break;
 							}
 						}
 					}
 				}
 			}
 		});
 		let (queue_in, queue_out) = mpsc::unbounded_channel();
 		let queue_out = Arc::new(Mutex::new(queue_out));
 		for i in 0..n_runners {
 			let queue_out = queue_out.clone();
 			let stop_signal = stop_signal.clone();
 			worker_in
 				.send(tokio::spawn(async move {
 					loop {
 						let (job, cancellable) = {
 							select! {
 								item = wait_job(&queue_out).fuse() => match item {
 									// We received a task, process it
 									Some(x) => x,
 									// We received a signal that no more tasks will ever be sent
 									// because the sending side was dropped. Exit now.
 									None => break,
 								},
 								_ = tokio::time::sleep(Duration::from_secs(5)).fuse() => {
 									if *stop_signal.borrow() {
 										// Nothing has been going on for 5 secs, and we are shutting
 										// down. Exit now.
 										break;
 									} else {
 										// Nothing is going on but we don't want to exit.
 										continue;
 									}
 								}
 							}
 						};
 						if cancellable && *stop_signal.borrow() {
 							continue;
 						}
 						if let Err(e) = job.await {
 							error!("Job failed: {}", e)
 						}
 					}
 					info!("Background worker {} exiting", i);
 				}))
 				.unwrap();
 		}
 		let bgrunner = Arc::new(Self {
 			stop_signal,
 			queue_in,
 			worker_in,
 		});
 		(bgrunner, await_all_done)
 	}
 	/// Spawn a task to be run in background
 	pub fn spawn<T>(&self, job: T)
 	where
 		T: Future<Output = JobOutput> + Send + 'static,
 	{
 		let boxed: Job = Box::pin(job);
 		self.queue_in
 			.send((boxed, false))
 			.map_err(|_| "could not put job in queue")
 			.unwrap();
 	}
 	/// Spawn a task to be run in background. It may get discarded before running if spawned while
 	/// the runner is stopping
 	pub fn spawn_cancellable<T>(&self, job: T)
 	where
 		T: Future<Output = JobOutput> + Send + 'static,
 	{
 		let boxed: Job = Box::pin(job);
 		self.queue_in
 			.send((boxed, true))
 			.map_err(|_| "could not put job in queue")
 			.unwrap();
 	}
 	pub fn spawn_worker<F, T>(&self, name: String, worker: F)
 	where
 		F: FnOnce(watch::Receiver<bool>) -> T + Send + 'static,
 		T: Future<Output = ()> + Send + 'static,
 	{
 		let stop_signal = self.stop_signal.clone();
 		let task = tokio::spawn(async move {
 			info!("Worker started: {}", name);
 			worker(stop_signal).await;
 			info!("Worker exited: {}", name);
 		});
 		self.worker_in
 			.send(task)
 			.map_err(|_| "could not put job in queue")
 			.unwrap();
 	}
 }
 async fn wait_job(q: &Mutex<mpsc::UnboundedReceiver<(Job, bool)>>) -> Option<(Job, bool)> {
 	q.lock().await.recv().await
 }
--- a/src/util/background/job_worker.rs
+++ b/src/util/background/job_worker.rs
@ -0,0 +1,48 @@
 //! Job worker: a generic worker that just processes incoming
 //! jobs one by one
 use std::sync::Arc;
 use async_trait::async_trait;
 use tokio::sync::{mpsc, Mutex};
 use crate::background::worker::*;
 use crate::background::*;
 pub(crate) struct JobWorker {
 	pub(crate) index: usize,
 	pub(crate) job_chan: Arc<Mutex<mpsc::UnboundedReceiver<(Job, bool)>>>,
 	pub(crate) next_job: Option<Job>,
 }
 #[async_trait]
 impl Worker for JobWorker {
 	fn name(&self) -> String {
 		format!("Job worker #{}", self.index)
 	}
 	async fn work(&mut self, _must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error> {
 		match self.next_job.take() {
 			None => return Ok(WorkerState::Idle),
 			Some(job) => {
 				job.await?;
 				Ok(WorkerState::Busy)
 			}
 		}
 	}
 	async fn wait_for_work(&mut self, must_exit: &watch::Receiver<bool>) -> WorkerState {
 		loop {
 			match self.job_chan.lock().await.recv().await {
 				Some((job, cancellable)) => {
 					if cancellable && *must_exit.borrow() {
 						continue;
 					}
 					self.next_job = Some(job);
 					return WorkerState::Busy;
 				}
 				None => return WorkerState::Done,
 			}
 		}
 	}
 }
--- a/src/util/background/mod.rs
+++ b/src/util/background/mod.rs
@ -0,0 +1,117 @@
 //! Job runner for futures and async functions
 pub mod job_worker;
 pub mod worker;
 use core::future::Future;
 use std::collections::HashMap;
 use std::pin::Pin;
 use std::sync::Arc;
 use serde::{Deserialize, Serialize};
 use tokio::sync::{mpsc, watch, Mutex};
 use crate::error::Error;
 use worker::WorkerProcessor;
 pub use worker::{Worker, WorkerState};
 pub(crate) type JobOutput = Result<(), Error>;
 pub(crate) type Job = Pin<Box<dyn Future<Output = JobOutput> + Send>>;
 /// Job runner for futures and async functions
 pub struct BackgroundRunner {
 	send_job: mpsc::UnboundedSender<(Job, bool)>,
 	send_worker: mpsc::UnboundedSender<Box<dyn Worker>>,
 	worker_info: Arc<std::sync::Mutex<HashMap<usize, WorkerInfo>>>,
 }
 #[derive(Clone, Serialize, Deserialize, Debug)]
 pub struct WorkerInfo {
 	pub name: String,
 	pub info: Option<String>,
 	pub state: WorkerState,
 	pub errors: usize,
 	pub consecutive_errors: usize,
 	pub last_error: Option<(String, u64)>,
 }
 impl BackgroundRunner {
 	/// Create a new BackgroundRunner
 	pub fn new(
 		n_runners: usize,
 		stop_signal: watch::Receiver<bool>,
 	) -> (Arc<Self>, tokio::task::JoinHandle<()>) {
 		let (send_worker, worker_out) = mpsc::unbounded_channel::<Box<dyn Worker>>();
 		let worker_info = Arc::new(std::sync::Mutex::new(HashMap::new()));
 		let mut worker_processor =
 			WorkerProcessor::new(worker_out, stop_signal, worker_info.clone());
 		let await_all_done = tokio::spawn(async move {
 			worker_processor.run().await;
 		});
 		let (send_job, queue_out) = mpsc::unbounded_channel();
 		let queue_out = Arc::new(Mutex::new(queue_out));
 		for i in 0..n_runners {
 			let queue_out = queue_out.clone();
 			send_worker
 				.send(Box::new(job_worker::JobWorker {
 					index: i,
 					job_chan: queue_out.clone(),
 					next_job: None,
 				}))
 				.ok()
 				.unwrap();
 		}
 		let bgrunner = Arc::new(Self {
 			send_job,
 			send_worker,
 			worker_info,
 		});
 		(bgrunner, await_all_done)
 	}
 	pub fn get_worker_info(&self) -> HashMap<usize, WorkerInfo> {
 		self.worker_info.lock().unwrap().clone()
 	}
 	/// Spawn a task to be run in background
 	pub fn spawn<T>(&self, job: T)
 	where
 		T: Future<Output = JobOutput> + Send + 'static,
 	{
 		let boxed: Job = Box::pin(job);
 		self.send_job
 			.send((boxed, false))
 			.ok()
 			.expect("Could not put job in queue");
 	}
 	/// Spawn a task to be run in background. It may get discarded before running if spawned while
 	/// the runner is stopping
 	pub fn spawn_cancellable<T>(&self, job: T)
 	where
 		T: Future<Output = JobOutput> + Send + 'static,
 	{
 		let boxed: Job = Box::pin(job);
 		self.send_job
 			.send((boxed, true))
 			.ok()
 			.expect("Could not put job in queue");
 	}
 	pub fn spawn_worker<W>(&self, worker: W)
 	where
 		W: Worker + 'static,
 	{
 		self.send_worker
 			.send(Box::new(worker))
 			.ok()
 			.expect("Could not put worker in queue");
 	}
 }
--- a/src/util/background/worker.rs
+++ b/src/util/background/worker.rs
@ -0,0 +1,261 @@
 use std::collections::HashMap;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
 use async_trait::async_trait;
 use futures::future::*;
 use futures::stream::FuturesUnordered;
 use futures::StreamExt;
 use serde::{Deserialize, Serialize};
 use tokio::select;
 use tokio::sync::{mpsc, watch};
 use tracing::*;
 use crate::background::WorkerInfo;
 use crate::error::Error;
 use crate::time::now_msec;
 #[derive(PartialEq, Copy, Clone, Serialize, Deserialize, Debug)]
 pub enum WorkerState {
 	Busy,
 	Throttled(f32),
 	Idle,
 	Done,
 }
 impl std::fmt::Display for WorkerState {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		match self {
 			WorkerState::Busy => write!(f, "Busy"),
 			WorkerState::Throttled(t) => write!(f, "Thr:{:.3}", t),
 			WorkerState::Idle => write!(f, "Idle"),
 			WorkerState::Done => write!(f, "Done"),
 		}
 	}
 }
 #[async_trait]
 pub trait Worker: Send {
 	fn name(&self) -> String;
 	fn info(&self) -> Option<String> {
 		None
 	}
 	/// Work: do a basic unit of work, if one is available (otherwise, should return
 	/// WorkerState::Idle immediately).  We will do our best to not interrupt this future in the
 	/// middle of processing, it will only be interrupted at the last minute when Garage is trying
 	/// to exit and this hasn't returned yet. This function may return an error to indicate that
 	/// its unit of work could not be processed due to an error: the error will be logged and
 	/// .work() will be called again after a short delay.
 	async fn work(&mut self, must_exit: &mut watch::Receiver<bool>) -> Result<WorkerState, Error>;
 	/// Wait for work: await for some task to become available.  This future can be interrupted in
 	/// the middle for any reason.  This future doesn't have to await on must_exit.changed(), we
 	/// are doing it for you.  Therefore it only receives a read refernce to must_exit which allows
 	/// it to check if we are exiting.
 	async fn wait_for_work(&mut self, must_exit: &watch::Receiver<bool>) -> WorkerState;
 }
 pub(crate) struct WorkerProcessor {
 	stop_signal: watch::Receiver<bool>,
 	worker_chan: mpsc::UnboundedReceiver<Box<dyn Worker>>,
 	worker_info: Arc<std::sync::Mutex<HashMap<usize, WorkerInfo>>>,
 }
 impl WorkerProcessor {
 	pub(crate) fn new(
 		worker_chan: mpsc::UnboundedReceiver<Box<dyn Worker>>,
 		stop_signal: watch::Receiver<bool>,
 		worker_info: Arc<std::sync::Mutex<HashMap<usize, WorkerInfo>>>,
 	) -> Self {
 		Self {
 			stop_signal,
 			worker_chan,
 			worker_info,
 		}
 	}
 	pub(crate) async fn run(&mut self) {
 		let mut workers = FuturesUnordered::new();
 		let mut next_task_id = 1;
 		while !*self.stop_signal.borrow() {
 			let await_next_worker = async {
 				if workers.is_empty() {
 					futures::future::pending().await
 				} else {
 					workers.next().await
 				}
 			};
 			select! {
 				new_worker_opt = self.worker_chan.recv() => {
 					if let Some(new_worker) = new_worker_opt {
 						let task_id = next_task_id;
 						next_task_id += 1;
 						let stop_signal = self.stop_signal.clone();
 						let stop_signal_worker = self.stop_signal.clone();
 						let mut worker = WorkerHandler {
 								task_id,
 								stop_signal,
 								stop_signal_worker,
 								worker: new_worker,
 								state: WorkerState::Busy,
 								errors: 0,
 								consecutive_errors: 0,
 								last_error: None,
 							};
 						workers.push(async move {
 							worker.step().await;
 							worker
 						}.boxed());
 					}
 				}
 				worker = await_next_worker => {
 					if let Some(mut worker) = worker {
 						trace!("{} (TID {}): {:?}", worker.worker.name(), worker.task_id, worker.state);
 						// Save worker info
 						let mut wi = self.worker_info.lock().unwrap();
 						match wi.get_mut(&worker.task_id) {
 							Some(i) => {
 								i.state = worker.state;
 								i.info = worker.worker.info();
 								i.errors = worker.errors;
 								i.consecutive_errors = worker.consecutive_errors;
 								if worker.last_error.is_some() {
 									i.last_error = worker.last_error.take();
 								}
 							}
 							None => {
 								wi.insert(worker.task_id, WorkerInfo {
 									name: worker.worker.name(),
 									state: worker.state,
 									info: worker.worker.info(),
 									errors: worker.errors,
 									consecutive_errors: worker.consecutive_errors,
 									last_error: worker.last_error.take(),
 								});
 							}
 						}
 						if worker.state == WorkerState::Done {
 							info!("Worker {} (TID {}) exited", worker.worker.name(), worker.task_id);
 						} else {
 							workers.push(async move {
 								worker.step().await;
 								worker
 							}.boxed());
 						}
 					}
 				}
 				_ = self.stop_signal.changed() => (),
 			}
 		}
 		// We are exiting, drain everything
 		let drain_half_time = Instant::now() + Duration::from_secs(5);
 		let drain_everything = async move {
 			while let Some(mut worker) = workers.next().await {
 				if worker.state == WorkerState::Done {
 					info!(
 						"Worker {} (TID {}) exited",
 						worker.worker.name(),
 						worker.task_id
 					);
 				} else if Instant::now() > drain_half_time {
 					warn!("Worker {} (TID {}) interrupted between two iterations in state {:?} (this should be fine)", worker.worker.name(), worker.task_id, worker.state);
 				} else {
 					workers.push(
 						async move {
 							worker.step().await;
 							worker
 						}
 						.boxed(),
 					);
 				}
 			}
 		};
 		select! {
 			_ = drain_everything => {
 				info!("All workers exited peacefully \\o/");
 			}
 			_ = tokio::time::sleep(Duration::from_secs(9)) => {
 				error!("Some workers could not exit in time, we are cancelling some things in the middle");
 			}
 		}
 	}
 }
 struct WorkerHandler {
 	task_id: usize,
 	stop_signal: watch::Receiver<bool>,
 	stop_signal_worker: watch::Receiver<bool>,
 	worker: Box<dyn Worker>,
 	state: WorkerState,
 	errors: usize,
 	consecutive_errors: usize,
 	last_error: Option<(String, u64)>,
 }
 impl WorkerHandler {
 	async fn step(&mut self) {
 		match self.state {
 			WorkerState::Busy => match self.worker.work(&mut self.stop_signal).await {
 				Ok(s) => {
 					self.state = s;
 					self.consecutive_errors = 0;
 				}
 				Err(e) => {
 					error!(
 						"Error in worker {} (TID {}): {}",
 						self.worker.name(),
 						self.task_id,
 						e
 					);
 					self.errors += 1;
 					self.consecutive_errors += 1;
 					self.last_error = Some((format!("{}", e), now_msec()));
 					// Sleep a bit so that error won't repeat immediately, exponential backoff
 					// strategy (min 1sec, max ~60sec)
 					self.state = WorkerState::Throttled(
 						(1.5f32).powf(std::cmp::min(10, self.consecutive_errors - 1) as f32),
 					);
 				}
 			},
 			WorkerState::Throttled(delay) => {
 				// Sleep for given delay and go back to busy state
 				if !*self.stop_signal.borrow() {
 					select! {
 						_ = tokio::time::sleep(Duration::from_secs_f32(delay)) => (),
 						_ = self.stop_signal.changed() => (),
 					}
 				}
 				self.state = WorkerState::Busy;
 			}
 			WorkerState::Idle => {
 				if *self.stop_signal.borrow() {
 					select! {
 						new_st = self.worker.wait_for_work(&self.stop_signal_worker) => {
 							self.state = new_st;
 						}
 						_ = tokio::time::sleep(Duration::from_secs(1)) => {
 							// stay in Idle state
 						}
 					}
 				} else {
 					select! {
 						new_st = self.worker.wait_for_work(&self.stop_signal_worker) => {
 							self.state = new_st;
 						}
 						_ = self.stop_signal.changed() => {
 							// stay in Idle state
 						}
 					}
 				}
 			}
 			WorkerState::Done => unreachable!(),
 		}
 	}
 }
--- a/src/util/lib.rs
+++ b/src/util/lib.rs
@ -11,7 +11,6 @@ pub mod error;
 pub mod formater;
 pub mod metrics;
 pub mod persister;
 //pub mod sled_counter;
 pub mod time;
 pub mod token_bucket;
 pub mod tranquilizer;
--- a/src/util/tranquilizer.rs
+++ b/src/util/tranquilizer.rs
@ -3,6 +3,8 @@ use std::time::{Duration, Instant};
 use tokio::time::sleep;
 use crate::background::WorkerState;
 /// A tranquilizer is a helper object that is used to make
 /// background operations not take up too much time.
 ///
@ -33,7 +35,7 @@ impl Tranquilizer {
 		}
 	}
-	pub async fn tranquilize(&mut self, tranquility: u32) {
+	fn tranquilize_internal(&mut self, tranquility: u32) -> Option<Duration> {
 		let observation = Instant::now() - self.last_step_begin;
 		self.observations.push_back(observation);
@ -45,13 +47,32 @@ impl Tranquilizer {
 		if !self.observations.is_empty() {
 			let delay = (tranquility * self.sum_observations) / (self.observations.len() as u32);
-			sleep(delay).await;
+			Some(delay)
 		} else {
 			None
 		}
 	}
-		self.reset();
+	pub async fn tranquilize(&mut self, tranquility: u32) {
 		if let Some(delay) = self.tranquilize_internal(tranquility) {
 			sleep(delay).await;
 			self.reset();
 		}
 	}
 	#[must_use]
 	pub fn tranquilize_worker(&mut self, tranquility: u32) -> WorkerState {
 		match self.tranquilize_internal(tranquility) {
 			Some(delay) => WorkerState::Throttled(delay.as_secs_f32()),
 			None => WorkerState::Busy,
 		}
 	}
 	pub fn reset(&mut self) {
 		self.last_step_begin = Instant::now();
 	}
 	pub fn clear(&mut self) {
 		self.observations.clear();
 	}
 }