diff --git a/weed/filer/filechunks.go b/weed/filer/filechunks.go
index 68f308a51..346eb3cfb 100644
--- a/weed/filer/filechunks.go
+++ b/weed/filer/filechunks.go
@@ -2,7 +2,6 @@ package filer
 
 import (
 	"bytes"
-	"encoding/hex"
 	"fmt"
 	"github.com/chrislusf/seaweedfs/weed/wdclient"
 	"math"
@@ -43,12 +42,11 @@ func ETagEntry(entry *Entry) (etag string) {
 
 func ETagChunks(chunks []*filer_pb.FileChunk) (etag string) {
 	if len(chunks) == 1 {
-		return chunks[0].ETag
+		return fmt.Sprintf("%x", util.Base64Md5ToBytes(chunks[0].ETag))
 	}
 	md5_digests := [][]byte{}
 	for _, c := range chunks {
-		md5_decoded, _ := hex.DecodeString(c.ETag)
-		md5_digests = append(md5_digests, md5_decoded)
+		md5_digests = append(md5_digests, util.Base64Md5ToBytes(c.ETag))
 	}
 	return fmt.Sprintf("%x-%d", util.Md5(bytes.Join(md5_digests, nil)), len(chunks))
 }
diff --git a/weed/operation/upload_content.go b/weed/operation/upload_content.go
index 944186eeb..8e7c6f733 100644
--- a/weed/operation/upload_content.go
+++ b/weed/operation/upload_content.go
@@ -39,7 +39,7 @@ func (uploadResult *UploadResult) ToPbFileChunk(fileId string, offset int64) *fi
 		Offset:       offset,
 		Size:         uint64(uploadResult.Size),
 		Mtime:        time.Now().UnixNano(),
-		ETag:         uploadResult.ETag,
+		ETag:         uploadResult.ContentMd5,
 		CipherKey:    uploadResult.CipherKey,
 		IsCompressed: uploadResult.Gzip > 0,
 		Fid:          fid,
diff --git a/weed/server/filer_server_handlers_write_upload.go b/weed/server/filer_server_handlers_write_upload.go
index 3ab45453e..b15deb9d1 100644
--- a/weed/server/filer_server_handlers_write_upload.go
+++ b/weed/server/filer_server_handlers_write_upload.go
@@ -1,6 +1,7 @@
 package weed_server
 
 import (
+	"bytes"
 	"crypto/md5"
 	"hash"
 	"io"
@@ -71,6 +72,11 @@ func (fs *FilerServer) uploadReaderToChunks(w http.ResponseWriter, r *http.Reque
 		if uploadResult.Size == 0 {
 			break
 		}
+		uploadedMd5 := util.Base64Md5ToBytes(uploadResult.ContentMd5)
+		readedMd5 := md5Hash.Sum(nil)
+		if !bytes.Equal(uploadedMd5, readedMd5) {
+			glog.Errorf("md5 %x does not match %x uploaded chunk %s to the volume server", readedMd5, uploadedMd5, uploadResult.Name)
+		}
 
 		// Save to chunk manifest structure
 		fileChunks = append(fileChunks, uploadResult.ToPbFileChunk(fileId, chunkOffset))