Ability to dynamically set resync tranquility

src/block/manager.rs

@@ -3,7 +3,7 @@ use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::Duration;
 
-use arc_swap::ArcSwapOption;
+use arc_swap::{ArcSwap, ArcSwapOption};
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 
@@ -25,6 +25,7 @@ use garage_util::background::*;
 use garage_util::data::*;
 use garage_util::error::*;
 use garage_util::metrics::RecordDuration;
+use garage_util::persister::Persister;
 use garage_util::time::*;
 use garage_util::tranquilizer::Tranquilizer;
 
@@ -55,6 +56,10 @@ const RESYNC_RETRY_DELAY: Duration = Duration::from_secs(60);
 // The maximum retry delay is 60 seconds * 2^6 = 60 seconds << 6 = 64 minutes (~1 hour)
 const RESYNC_RETRY_DELAY_MAX_BACKOFF_POWER: u64 = 6;
 
+// Resync tranquility is initially set to 2, but can be changed in the CLI
+// and the updated version is persisted over Garage restarts
+const INITIAL_RESYNC_TRANQUILITY: u32 = 2;
+
 // The delay between the moment when the reference counter
 // drops to zero, and the moment where we allow ourselves
 // to delete the block locally.
@@ -90,7 +95,6 @@ pub struct BlockManager {
 	pub data_dir: PathBuf,
 
 	compression_level: Option<i32>,
-	background_tranquility: u32,
 
 	mutation_lock: Mutex<BlockManagerLocked>,
 
@@ -100,6 +104,9 @@ pub struct BlockManager {
 	resync_notify: Notify,
 	resync_errors: CountedTree,
 
+	resync_persister: Persister<ResyncPersistedConfig>,
+	resync_persisted: ArcSwap<ResyncPersistedConfig>,
+
 	pub(crate) system: Arc<System>,
 	endpoint: Arc<Endpoint<BlockRpc, Self>>,
 
@@ -124,7 +131,6 @@ impl BlockManager {
 		db: &db::Db,
 		data_dir: PathBuf,
 		compression_level: Option<i32>,
-		background_tranquility: u32,
 		replication: TableShardedReplication,
 		system: Arc<System>,
 	) -> Arc<Self> {
@@ -145,6 +151,14 @@ impl BlockManager {
 		let resync_errors =
 			CountedTree::new(resync_errors).expect("Could not count block_local_resync_errors");
 
+		let resync_persister = Persister::new(&system.metadata_dir, "resync_cfg");
+		let resync_persisted = match resync_persister.load() {
+			Ok(v) => v,
+			Err(_) => ResyncPersistedConfig {
+				tranquility: INITIAL_RESYNC_TRANQUILITY,
+			},
+		};
+
 		let endpoint = system
 			.netapp
 			.endpoint("garage_block/manager.rs/Rpc".to_string());
@@ -157,12 +171,13 @@ impl BlockManager {
 			replication,
 			data_dir,
 			compression_level,
-			background_tranquility,
 			mutation_lock: Mutex::new(manager_locked),
 			rc,
 			resync_queue,
 			resync_notify: Notify::new(),
 			resync_errors,
+			resync_persister,
+			resync_persisted: ArcSwap::new(Arc::new(resync_persisted)),
 			system,
 			endpoint,
 			metrics,
@@ -716,6 +731,23 @@ impl BlockManager {
 
 		Ok(())
 	}
+
+	async fn update_resync_persisted(
+		&self,
+		update: impl Fn(&mut ResyncPersistedConfig),
+	) -> Result<(), Error> {
+		let mut cfg: ResyncPersistedConfig = *self.resync_persisted.load().as_ref();
+		update(&mut cfg);
+		self.resync_persister.save_async(&cfg).await?;
+		self.resync_persisted.store(Arc::new(cfg));
+		self.resync_notify.notify_one();
+		Ok(())
+	}
+
+	pub async fn set_resync_tranquility(&self, tranquility: u32) -> Result<(), Error> {
+		self.update_resync_persisted(|cfg| cfg.tranquility = tranquility)
+			.await
+	}
 }
 
 #[async_trait]
@@ -734,6 +766,11 @@ impl EndpointHandler<BlockRpc> for BlockManager {
 	}
 }
 
+#[derive(Serialize, Deserialize, Clone, Copy)]
+struct ResyncPersistedConfig {
+	tranquility: u32,
+}
+
 struct ResyncWorker {
 	manager: Arc<BlockManager>,
 	tranquilizer: Tranquilizer,
@@ -758,19 +795,22 @@ impl Worker for ResyncWorker {
 
 	fn info(&self) -> Option<String> {
 		let mut ret = vec![];
+		ret.push(format!(
+			"tranquility = {}",
+			self.manager.resync_persisted.load().tranquility
+		));
+
 		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));
 		}
+
+		let elen = self.manager.resync_errors_len().unwrap_or(0);
 		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> {
@@ -778,7 +818,7 @@ impl Worker for ResyncWorker {
 		match self.manager.resync_iter().await {
 			Ok(ResyncIterResult::BusyDidSomething) => Ok(self
 				.tranquilizer
-				.tranquilize_worker(self.manager.background_tranquility)),
+				.tranquilize_worker(self.manager.resync_persisted.load().tranquility)),
 			Ok(ResyncIterResult::BusyDidNothing) => Ok(WorkerState::Busy),
 			Ok(ResyncIterResult::IdleFor(delay)) => {
 				self.next_delay = delay;

src/block/repair.rs

@@ -19,7 +19,17 @@ use garage_util::tranquilizer::Tranquilizer;
 
 use crate::manager::*;
 
-const SCRUB_INTERVAL: Duration = Duration::from_secs(3600 * 24 * 30); // full scrub every 30 days
+// Full scrub every 30 days
+const SCRUB_INTERVAL: Duration = Duration::from_secs(3600 * 24 * 30);
+// Scrub tranquility is initially set to 4, but can be changed in the CLI
+// and the updated version is persisted over Garage restarts
+const INITIAL_SCRUB_TRANQUILITY: u32 = 4;
+
+// ---- ---- ----
+// FIRST KIND OF REPAIR: FINDING MISSING BLOCKS/USELESS BLOCKS
+// This is a one-shot repair operation that can be launched,
+// checks everything, and then exits.
+// ---- ---- ----
 
 pub struct RepairWorker {
 	manager: Arc<BlockManager>,
@@ -128,7 +138,13 @@ impl Worker for RepairWorker {
 	}
 }
 
-// ----
+// ---- ---- ----
+// SECOND KIND OF REPAIR: SCRUBBING THE DATASTORE
+// This is significantly more complex than the process above,
+// as it is a continuously-running task that triggers automatically
+// every SCRUB_INTERVAL, but can also be triggered manually
+// and whose parameter (esp. speed) can be controlled at runtime.
+// ---- ---- ----
 
 pub struct ScrubWorker {
 	manager: Arc<BlockManager>,
@@ -176,7 +192,7 @@ impl ScrubWorker {
 			Ok(v) => v,
 			Err(_) => ScrubWorkerPersisted {
 				time_last_complete_scrub: 0,
-				tranquility: 4,
+				tranquility: INITIAL_SCRUB_TRANQUILITY,
 				corruptions_detected: 0,
 			},
 		};
@@ -343,7 +359,9 @@ impl Worker for ScrubWorker {
 	}
 }
 
-// ----
+// ---- ---- ----
+// UTILITY FOR ENUMERATING THE BLOCK STORE
+// ---- ---- ----
 
 struct BlockStoreIterator {
 	path: Vec<ReadingDir>,

src/garage/admin.rs

@@ -15,6 +15,8 @@ use garage_table::*;
 
 use garage_rpc::*;
 
+use garage_block::repair::ScrubWorkerCommand;
+
 use garage_model::bucket_alias_table::*;
 use garage_model::bucket_table::*;
 use garage_model::garage::Garage;
@@ -836,6 +838,23 @@ impl AdminRpcHandler {
 				let workers = self.garage.background.get_worker_info();
 				Ok(AdminRpc::WorkerList(workers, opt))
 			}
+			WorkerCmd::Set { opt } => match opt {
+				WorkerSetCmd::ScrubTranquility { tranquility } => {
+					let scrub_command = ScrubWorkerCommand::SetTranquility(tranquility);
+					self.garage
+						.block_manager
+						.send_scrub_command(scrub_command)
+						.await;
+					Ok(AdminRpc::Ok("Scrub tranquility updated".into()))
+				}
+				WorkerSetCmd::ResyncTranquility { tranquility } => {
+					self.garage
+						.block_manager
+						.set_resync_tranquility(tranquility)
+						.await?;
+					Ok(AdminRpc::Ok("Resync tranquility updated".into()))
+				}
+			},
 		}
 	}
 }

src/garage/cli/structs.rs

@@ -501,6 +501,12 @@ pub enum WorkerCmd {
 		#[structopt(flatten)]
 		opt: WorkerListOpt,
 	},
+	/// Set worker parameter
+	#[structopt(name = "set", version = version::garage())]
+	Set {
+		#[structopt(subcommand)]
+		opt: WorkerSetCmd,
+	},
 }
 
 #[derive(Serialize, Deserialize, StructOpt, Debug, Eq, PartialEq, Clone, Copy)]
@@ -512,3 +518,13 @@ pub struct WorkerListOpt {
 	#[structopt(short = "e", long = "errors")]
 	pub errors: bool,
 }
+
+#[derive(Serialize, Deserialize, StructOpt, Debug, Eq, PartialEq, Clone)]
+pub enum WorkerSetCmd {
+	/// Set tranquility of scrub operations
+	#[structopt(name = "scrub-tranquility", version = version::garage())]
+	ScrubTranquility { tranquility: u32 },
+	/// Set tranquility of resync operations
+	#[structopt(name = "resync-tranquility", version = version::garage())]
+	ResyncTranquility { tranquility: u32 },
+}

src/model/garage.rs

@@ -159,7 +159,6 @@ impl Garage {
 			&db,
 			config.data_dir.clone(),
 			config.compression_level,
-			config.block_manager_background_tranquility,
 			data_rep_param,
 			system.clone(),
 		);

src/util/config.rs

@@ -23,10 +23,6 @@ pub struct Config {
 	#[serde(default = "default_block_size")]
 	pub block_size: usize,
 
-	/// Size of data blocks to save to disk
-	#[serde(default = "default_block_manager_background_tranquility")]
-	pub block_manager_background_tranquility: u32,
-
 	/// Replication mode. Supported values:
 	/// - none, 1 -> no replication
 	/// - 2 -> 2-way replication
@@ -147,9 +143,6 @@ fn default_sled_flush_every_ms() -> u64 {
 fn default_block_size() -> usize {
 	1048576
 }
-fn default_block_manager_background_tranquility() -> u32 {
-	2
-}
 
 /// Read and parse configuration
 pub fn read_config(config_file: PathBuf) -> Result<Config, Error> {