skip disks under scanning when healing disks (#17822)

Bonus:

- avoid calling DiskInfo() calls when missing blocks
  instead heal the object using MRF operation.

- change the max_sleep to 250ms beyond that we will
  not stop healing.

cmd/background-heal-ops.go

@@ -75,9 +75,9 @@ func waitForLowIO(maxIO int, maxWait time.Duration, currentIO func() int) {
 		if tmpMaxWait > 0 {
 			if tmpMaxWait < waitTick {
 				time.Sleep(tmpMaxWait)
-			} else {
-				time.Sleep(waitTick)
+				return
 			}
+			time.Sleep(waitTick)
 			tmpMaxWait -= waitTick
 		}
 		if tmpMaxWait <= 0 {

cmd/erasure-object.go

@@ -412,9 +412,14 @@ func (er erasureObjects) getObjectWithFileInfo(ctx context.Context, bucket, obje
 				switch scan {
 				case madmin.HealNormalScan, madmin.HealDeepScan:
 					healOnce.Do(func() {
-						if _, healing := er.getOnlineDisksWithHealing(); !healing {
-							go healObject(bucket, object, fi.VersionID, scan)
-						}
+						globalMRFState.addPartialOp(partialOperation{
+							bucket:    bucket,
+							object:    object,
+							versionID: fi.VersionID,
+							queued:    time.Now(),
+							setIndex:  er.setIndex,
+							poolIndex: er.poolIndex,
+						})
 					})
 					// Healing is triggered and we have written
 					// successfully the content to client for
@@ -732,9 +737,14 @@ func (er erasureObjects) getObjectFileInfo(ctx context.Context, bucket, object s
 	// additionally do not heal delete markers inline, let them be
 	// healed upon regular heal process.
 	if !fi.Deleted && missingBlocks > 0 && missingBlocks < readQuorum {
-		if _, healing := er.getOnlineDisksWithHealing(); !healing {
-			go healObject(bucket, object, fi.VersionID, madmin.HealNormalScan)
-		}
+		globalMRFState.addPartialOp(partialOperation{
+			bucket:    bucket,
+			object:    object,
+			versionID: fi.VersionID,
+			queued:    time.Now(),
+			setIndex:  er.setIndex,
+			poolIndex: er.poolIndex,
+		})
 	}
 
 	return fi, metaArr, onlineDisks, nil

cmd/erasure.go

@@ -309,6 +309,7 @@ func (er erasureObjects) getOnlineDisksWithHealing() (newDisks []StorageAPI, hea
 	}
 	wg.Wait()
 
+	var scanningDisks []StorageAPI
 	for i, info := range infos {
 		// Check if one of the drives in the set is being healed.
 		// this information is used by scanner to skip healing
@@ -317,9 +318,16 @@ func (er erasureObjects) getOnlineDisksWithHealing() (newDisks []StorageAPI, hea
 			healing = true
 			continue
 		}
-		newDisks = append(newDisks, disks[i])
+		if !info.Scanning {
+			newDisks = append(newDisks, disks[i])
+		} else {
+			scanningDisks = append(scanningDisks, disks[i])
+		}
 	}
 
+	// Prefer new disks over disks which are currently being scanned.
+	newDisks = append(newDisks, scanningDisks...)
+
 	return newDisks, healing
 }
 

cmd/global-heal.go

@@ -192,7 +192,7 @@ func (er *erasureObjects) healErasureSet(ctx context.Context, buckets []string,
 		tracker.setObject("")
 		tracker.setBucket(bucket)
 		// Heal current bucket again in case if it is failed
-		// in the  being of erasure set healing
+		// in the beginning of erasure set healing
 		if _, err := er.HealBucket(ctx, bucket, madmin.HealOpts{
 			ScanMode: scanMode,
 		}); err != nil {
@@ -241,7 +241,7 @@ func (er *erasureObjects) healErasureSet(ctx context.Context, buckets []string,
 		}
 
 		// Collect updates to tracker from concurrent healEntry calls
-		results := make(chan healEntryResult)
+		results := make(chan healEntryResult, 1000)
 		go func() {
 			for res := range results {
 				if res.entryDone {
@@ -256,6 +256,15 @@ func (er *erasureObjects) healErasureSet(ctx context.Context, buckets []string,
 			}
 		}()
 
+		send := func(result healEntryResult) bool {
+			select {
+			case <-ctx.Done():
+				return false
+			case results <- result:
+				return true
+			}
+		}
+
 		// Note: updates from healEntry to tracker must be sent on results channel.
 		healEntry := func(bucket string, entry metaCacheEntry) {
 			if entry.name == "" && len(entry.metadata) == 0 {
@@ -302,12 +311,7 @@ func (er *erasureObjects) healErasureSet(ctx context.Context, buckets []string,
 					result = healEntrySuccess(0)
 				}
 
-				select {
-				case <-ctx.Done():
-					return
-				case results <- result:
-				}
-
+				send(result)
 				return
 			}
 
@@ -342,10 +346,8 @@ func (er *erasureObjects) healErasureSet(ctx context.Context, buckets []string,
 				}
 				bgSeq.logHeal(madmin.HealItemObject)
 
-				select {
-				case <-ctx.Done():
+				if !send(result) {
 					return
-				case results <- result:
 				}
 			}
 			// All versions resulted in 'ObjectNotFound'

cmd/xl-storage-disk-id-check.go

@@ -93,7 +93,7 @@ type xlStorageDiskIDCheck struct {
 
 func (p *xlStorageDiskIDCheck) getMetrics() DiskMetrics {
 	p.metricsCache.Once.Do(func() {
-		p.metricsCache.TTL = 100 * time.Millisecond
+		p.metricsCache.TTL = 1 * time.Second
 		p.metricsCache.Update = func() (interface{}, error) {
 			diskMetric := DiskMetrics{
 				LastMinute: make(map[string]AccElem, len(p.apiLatencies)),

internal/config/heal/heal.go

@@ -97,7 +97,7 @@ var DefaultKVS = config.KVS{
 	},
 	config.KV{
 		Key:   Sleep,
-		Value: "1s",
+		Value: "250ms",
 	},
 	config.KV{
 		Key:   IOCount,