diff --git a/weed/command/filer_copy.go b/weed/command/filer_copy.go
index 19aceb211..1dd831cb6 100644
--- a/weed/command/filer_copy.go
+++ b/weed/command/filer_copy.go
@@ -29,16 +29,17 @@ var (
 )
 
 type CopyOptions struct {
-	include          *string
-	replication      *string
-	collection       *string
-	ttl              *string
-	maxMB            *int
-	masterClient     *wdclient.MasterClient
-	concurrency      *int
-	compressionLevel *int
-	grpcDialOption   grpc.DialOption
-	masters          []string
+	include           *string
+	replication       *string
+	collection        *string
+	ttl               *string
+	maxMB             *int
+	masterClient      *wdclient.MasterClient
+	concurrenctFiles  *int
+	concurrenctChunks *int
+	compressionLevel  *int
+	grpcDialOption    grpc.DialOption
+	masters           []string
 }
 
 func init() {
@@ -49,7 +50,8 @@ func init() {
 	copy.collection = cmdCopy.Flag.String("collection", "", "optional collection name")
 	copy.ttl = cmdCopy.Flag.String("ttl", "", "time to live, e.g.: 1m, 1h, 1d, 1M, 1y")
 	copy.maxMB = cmdCopy.Flag.Int("maxMB", 32, "split files larger than the limit")
-	copy.concurrency = cmdCopy.Flag.Int("c", 8, "concurrent file copy goroutines")
+	copy.concurrenctFiles = cmdCopy.Flag.Int("c", 8, "concurrent file copy goroutines")
+	copy.concurrenctChunks = cmdCopy.Flag.Int("concurrentChunks", 8, "concurrent chunk copy goroutines for each file")
 	copy.compressionLevel = cmdCopy.Flag.Int("compressionLevel", 9, "local file compression level 1 ~ 9")
 }
 
@@ -131,7 +133,7 @@ func runCopy(cmd *Command, args []string) bool {
 		util.SetupProfiling("filer.copy.cpu.pprof", "filer.copy.mem.pprof")
 	}
 
-	fileCopyTaskChan := make(chan FileCopyTask, *copy.concurrency)
+	fileCopyTaskChan := make(chan FileCopyTask, *copy.concurrenctFiles)
 
 	go func() {
 		defer close(fileCopyTaskChan)
@@ -142,7 +144,7 @@ func runCopy(cmd *Command, args []string) bool {
 			}
 		}
 	}()
-	for i := 0; i < *copy.concurrency; i++ {
+	for i := 0; i < *copy.concurrenctFiles; i++ {
 		waitGroup.Add(1)
 		go func() {
 			defer waitGroup.Done()
@@ -345,41 +347,66 @@ func (worker *FileCopyWorker) uploadFileInChunks(ctx context.Context, task FileC
 	fileName := filepath.Base(f.Name())
 	mimeType := detectMimeType(f)
 
+	chunksChan := make(chan *filer_pb.FileChunk, chunkCount)
+
+	concurrentChunks := make(chan struct{}, *worker.options.concurrenctChunks)
+	var wg sync.WaitGroup
+	var uploadError error
+
+	fmt.Printf("uploading %s in %d chunks ...\n", fileName, chunkCount)
+	for i := int64(0); i < int64(chunkCount) && uploadError == nil; i++ {
+		wg.Add(1)
+		concurrentChunks <- struct{}{}
+		go func(i int64) {
+			defer func() {
+				wg.Done()
+				<-concurrentChunks
+			}()
+			// assign a volume
+			assignResult, err := operation.Assign(worker.options.masterClient.GetMaster(), worker.options.grpcDialOption, &operation.VolumeAssignRequest{
+				Count:       1,
+				Replication: *worker.options.replication,
+				Collection:  *worker.options.collection,
+				Ttl:         *worker.options.ttl,
+			})
+			if err != nil {
+				fmt.Printf("Failed to assign from %v: %v\n", worker.options.masters, err)
+			}
+
+			targetUrl := "http://" + assignResult.Url + "/" + assignResult.Fid
+
+			uploadResult, err := operation.Upload(targetUrl,
+				fileName+"-"+strconv.FormatInt(i+1, 10),
+				io.NewSectionReader(f, i*chunkSize, chunkSize),
+				false, "application/octet-stream", nil, assignResult.Auth)
+			if err != nil {
+				uploadError = fmt.Errorf("upload data %v to %s: %v\n", fileName, targetUrl, err)
+				return
+			}
+			if uploadResult.Error != "" {
+				uploadError = fmt.Errorf("upload %v to %s result: %v\n", fileName, targetUrl, uploadResult.Error)
+				return
+			}
+			chunksChan <- &filer_pb.FileChunk{
+				FileId: assignResult.Fid,
+				Offset: i * chunkSize,
+				Size:   uint64(uploadResult.Size),
+				Mtime:  time.Now().UnixNano(),
+				ETag:   uploadResult.ETag,
+			}
+			fmt.Printf("uploaded %s-%d to %s [%d,%d)\n", fileName, i+1, targetUrl, i*chunkSize, i*chunkSize+int64(uploadResult.Size))
+		}(i)
+	}
+	wg.Wait()
+	close(chunksChan)
+
+	if uploadError != nil {
+		return uploadError
+	}
+
 	var chunks []*filer_pb.FileChunk
-
-	for i := int64(0); i < int64(chunkCount); i++ {
-
-		// assign a volume
-		assignResult, err := operation.Assign(worker.options.masterClient.GetMaster(), worker.options.grpcDialOption, &operation.VolumeAssignRequest{
-			Count:       1,
-			Replication: *worker.options.replication,
-			Collection:  *worker.options.collection,
-			Ttl:         *worker.options.ttl,
-		})
-		if err != nil {
-			fmt.Printf("Failed to assign from %v: %v\n", worker.options.masters, err)
-		}
-
-		targetUrl := "http://" + assignResult.Url + "/" + assignResult.Fid
-
-		uploadResult, err := operation.Upload(targetUrl,
-			fileName+"-"+strconv.FormatInt(i+1, 10),
-			io.LimitReader(f, chunkSize),
-			false, "application/octet-stream", nil, assignResult.Auth)
-		if err != nil {
-			return fmt.Errorf("upload data %v to %s: %v\n", fileName, targetUrl, err)
-		}
-		if uploadResult.Error != "" {
-			return fmt.Errorf("upload %v to %s result: %v\n", fileName, targetUrl, uploadResult.Error)
-		}
-		chunks = append(chunks, &filer_pb.FileChunk{
-			FileId: assignResult.Fid,
-			Offset: i * chunkSize,
-			Size:   uint64(uploadResult.Size),
-			Mtime:  time.Now().UnixNano(),
-			ETag:   uploadResult.ETag,
-		})
-		fmt.Printf("uploaded %s-%d to %s [%d,%d)\n", fileName, i+1, targetUrl, i*chunkSize, i*chunkSize+int64(uploadResult.Size))
+	for chunk := range chunksChan {
+		chunks = append(chunks, chunk)
 	}
 
 	if err := withFilerClient(ctx, worker.filerGrpcAddress, worker.options.grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {