optional parallel copy ec shards

fix https://github.com/chrislusf/seaweedfs/issues/2048

weed/shell/command_ec_encode.go

@@ -63,6 +63,7 @@ func (c *commandEcEncode) Do(args []string, commandEnv *CommandEnv, writer io.Wr
 	collection := encodeCommand.String("collection", "", "the collection name")
 	fullPercentage := encodeCommand.Float64("fullPercent", 95, "the volume reaches the percentage of max volume size")
 	quietPeriod := encodeCommand.Duration("quietFor", time.Hour, "select volumes without no writes for this period")
+	parallelCopy := encodeCommand.Bool("parallelCopy", true, "copy shards in parallel")
 	if err = encodeCommand.Parse(args); err != nil {
 		return nil
 	}
@@ -71,7 +72,7 @@ func (c *commandEcEncode) Do(args []string, commandEnv *CommandEnv, writer io.Wr
 
 	// volumeId is provided
 	if vid != 0 {
-		return doEcEncode(commandEnv, *collection, vid)
+		return doEcEncode(commandEnv, *collection, vid, *parallelCopy)
 	}
 
 	// apply to all volumes in the collection
@@ -81,7 +82,7 @@ func (c *commandEcEncode) Do(args []string, commandEnv *CommandEnv, writer io.Wr
 	}
 	fmt.Printf("ec encode volumes: %v\n", volumeIds)
 	for _, vid := range volumeIds {
-		if err = doEcEncode(commandEnv, *collection, vid); err != nil {
+		if err = doEcEncode(commandEnv, *collection, vid, *parallelCopy); err != nil {
 			return err
 		}
 	}
@@ -89,7 +90,7 @@ func (c *commandEcEncode) Do(args []string, commandEnv *CommandEnv, writer io.Wr
 	return nil
 }
 
-func doEcEncode(commandEnv *CommandEnv, collection string, vid needle.VolumeId) (err error) {
+func doEcEncode(commandEnv *CommandEnv, collection string, vid needle.VolumeId, parallelCopy bool) (err error) {
 	// find volume location
 	locations, found := commandEnv.MasterClient.GetLocations(uint32(vid))
 	if !found {
@@ -111,7 +112,7 @@ func doEcEncode(commandEnv *CommandEnv, collection string, vid needle.VolumeId)
 	}
 
 	// balance the ec shards to current cluster
-	err = spreadEcShards(commandEnv, vid, collection, locations)
+	err = spreadEcShards(commandEnv, vid, collection, locations, parallelCopy)
 	if err != nil {
 		return fmt.Errorf("spread ec shards for volume %d from %s: %v", vid, locations[0].Url, err)
 	}
@@ -157,7 +158,7 @@ func generateEcShards(grpcDialOption grpc.DialOption, volumeId needle.VolumeId,
 
 }
 
-func spreadEcShards(commandEnv *CommandEnv, volumeId needle.VolumeId, collection string, existingLocations []wdclient.Location) (err error) {
+func spreadEcShards(commandEnv *CommandEnv, volumeId needle.VolumeId, collection string, existingLocations []wdclient.Location, parallelCopy bool) (err error) {
 
 	allEcNodes, totalFreeEcSlots, err := collectEcNodes(commandEnv, "")
 	if err != nil {
@@ -176,7 +177,7 @@ func spreadEcShards(commandEnv *CommandEnv, volumeId needle.VolumeId, collection
 	allocatedEcIds := balancedEcDistribution(allocatedDataNodes)
 
 	// ask the data nodes to copy from the source volume server
-	copiedShardIds, err := parallelCopyEcShardsFromSource(commandEnv.option.GrpcDialOption, allocatedDataNodes, allocatedEcIds, volumeId, collection, existingLocations[0])
+	copiedShardIds, err := parallelCopyEcShardsFromSource(commandEnv.option.GrpcDialOption, allocatedDataNodes, allocatedEcIds, volumeId, collection, existingLocations[0], parallelCopy)
 	if err != nil {
 		return err
 	}
@@ -206,30 +207,36 @@ func spreadEcShards(commandEnv *CommandEnv, volumeId needle.VolumeId, collection
 
 }
 
-func parallelCopyEcShardsFromSource(grpcDialOption grpc.DialOption, targetServers []*EcNode, allocatedEcIds [][]uint32, volumeId needle.VolumeId, collection string, existingLocation wdclient.Location) (actuallyCopied []uint32, err error) {
+func parallelCopyEcShardsFromSource(grpcDialOption grpc.DialOption, targetServers []*EcNode, allocatedEcIds [][]uint32, volumeId needle.VolumeId, collection string, existingLocation wdclient.Location, parallelCopy bool) (actuallyCopied []uint32, err error) {
 
 	fmt.Printf("parallelCopyEcShardsFromSource %d %s\n", volumeId, existingLocation.Url)
 
-	// parallelize
-	shardIdChan := make(chan []uint32, len(targetServers))
 	var wg sync.WaitGroup
+	shardIdChan := make(chan []uint32, len(targetServers))
+	copyFunc := func(server *EcNode, allocatedEcShardIds []uint32) {
+		defer wg.Done()
+		copiedShardIds, copyErr := oneServerCopyAndMountEcShardsFromSource(grpcDialOption, server,
+			allocatedEcShardIds, volumeId, collection, existingLocation.Url)
+		if copyErr != nil {
+			err = copyErr
+		} else {
+			shardIdChan <- copiedShardIds
+			server.addEcVolumeShards(volumeId, collection, copiedShardIds)
+		}
+	}
+
+	// maybe parallelize
 	for i, server := range targetServers {
 		if len(allocatedEcIds[i]) <= 0 {
 			continue
 		}
 
 		wg.Add(1)
-		go func(server *EcNode, allocatedEcShardIds []uint32) {
-			defer wg.Done()
-			copiedShardIds, copyErr := oneServerCopyAndMountEcShardsFromSource(grpcDialOption, server,
-				allocatedEcShardIds, volumeId, collection, existingLocation.Url)
-			if copyErr != nil {
-				err = copyErr
-			} else {
-				shardIdChan <- copiedShardIds
-				server.addEcVolumeShards(volumeId, collection, copiedShardIds)
-			}
-		}(server, allocatedEcIds[i])
+		if parallelCopy {
+			go copyFunc(server, allocatedEcIds[i])
+		} else {
+			copyFunc(server, allocatedEcIds[i])
+		}
 	}
 	wg.Wait()
 	close(shardIdChan)