diff --git a/weed/command/scaffold.go b/weed/command/scaffold.go
index e0bd48c8c..fbe6934e1 100644
--- a/weed/command/scaffold.go
+++ b/weed/command/scaffold.go
@@ -178,6 +178,7 @@ collection = ""
 ttlSec = 0
 
 [sink.s3]
+# experimental
 # See https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/sessions.html
 # default loads credentials from the shared credentials file (~/.aws/credentials). 
 enabled = false
@@ -187,5 +188,14 @@ region = "us-east-2"
 bucket = "your_bucket_name"    # an existing bucket
 directory = ""                 # destination directory (do not prefix or suffix with "/")
 
+[sink.google_cloud_storage]
+# experimental
+# see https://cloud.google.com/docs/authentication/getting-started
+enabled = false
+google_application_credentials = "/path/to/x.json" # path to json credential file
+projectId = "your_project_id"
+bucket = "your_bucket_name"    # an existing bucket
+directory = "/"                 # destination directory
+
 `
 )
diff --git a/weed/replication/sink/gcssink/gcs_sink.go b/weed/replication/sink/gcssink/gcs_sink.go
new file mode 100644
index 000000000..f96cae7df
--- /dev/null
+++ b/weed/replication/sink/gcssink/gcs_sink.go
@@ -0,0 +1,130 @@
+package gcssink
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"cloud.google.com/go/storage"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/replication/source"
+	"github.com/chrislusf/seaweedfs/weed/util"
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/replication/sink"
+	"os"
+	"google.golang.org/api/option"
+)
+
+type GcsSink struct {
+	client      *storage.Client
+	projectId   string
+	bucket      string
+	dir         string
+	filerSource *source.FilerSource
+}
+
+func init() {
+	sink.Sinks = append(sink.Sinks, &GcsSink{})
+}
+
+func (g *GcsSink) GetName() string {
+	return "google_cloud_storage"
+}
+
+func (g *GcsSink) GetSinkToDirectory() string {
+	return g.dir
+}
+
+func (g *GcsSink) Initialize(configuration util.Configuration) error {
+	return g.initialize(
+		configuration.GetString("google_application_credentials"),
+		configuration.GetString("projectId"),
+		configuration.GetString("bucket"),
+		configuration.GetString("directory"),
+	)
+}
+
+func (g *GcsSink) SetSourceFiler(s *source.FilerSource) {
+	g.filerSource = s
+}
+
+func (g *GcsSink) initialize(google_application_credentials, projectId, bucketName, dir string) (error) {
+	g.projectId = projectId
+	g.bucket = bucketName
+	g.dir = dir
+
+	ctx := context.Background()
+	// Creates a client.
+	if google_application_credentials == "" {
+		var found bool
+		google_application_credentials, found = os.LookupEnv("GOOGLE_APPLICATION_CREDENTIALS")
+		if !found {
+			log.Fatalf("need to specific GOOGLE_APPLICATION_CREDENTIALS env variable or google_application_credentials in replication.toml")
+		}
+	}
+	client, err := storage.NewClient(ctx, option.WithCredentialsFile(google_application_credentials))
+	if err != nil {
+		log.Fatalf("Failed to create client: %v", err)
+	}
+
+	g.client = client
+
+	return nil
+}
+
+func (g *GcsSink) DeleteEntry(key string, isDirectory, deleteIncludeChunks bool) error {
+
+	if isDirectory {
+		key = key + "/"
+	}
+
+	if err := g.client.Bucket(g.bucket).Object(key).Delete(context.Background()); err != nil {
+		return fmt.Errorf("gcs delete %s %s", g.bucket, key)
+	}
+
+	return nil
+
+}
+
+func (g *GcsSink) CreateEntry(key string, entry *filer_pb.Entry) error {
+
+	if entry.IsDirectory {
+		return nil
+	}
+
+	totalSize := filer2.TotalSize(entry.Chunks)
+	chunkViews := filer2.ViewFromChunks(entry.Chunks, 0, int(totalSize))
+
+	ctx := context.Background()
+
+	wc := g.client.Bucket(g.bucket).Object(key).NewWriter(ctx)
+
+	for _, chunk := range chunkViews {
+
+		fileUrl, err := g.filerSource.LookupFileId(chunk.FileId)
+		if err != nil {
+			return err
+		}
+
+		_, err = util.ReadUrlAsStream(fileUrl, chunk.Offset, int(chunk.Size), func(data []byte) {
+			wc.Write(data)
+		})
+
+		if err != nil {
+			return err
+		}
+
+	}
+
+	if err := wc.Close(); err != nil {
+		return err
+	}
+
+	return nil
+
+}
+
+func (g *GcsSink) UpdateEntry(key string, oldEntry, newEntry *filer_pb.Entry, deleteIncludeChunks bool) (foundExistingEntry bool, err error) {
+	// TODO improve efficiency
+	return false, nil
+}
diff --git a/weed/replication/sink/s3sink/s3_sink.go b/weed/replication/sink/s3sink/s3_sink.go
index c8300a108..ee2e46422 100644
--- a/weed/replication/sink/s3sink/s3_sink.go
+++ b/weed/replication/sink/s3sink/s3_sink.go
@@ -17,7 +17,6 @@ import (
 )
 
 type S3Sink struct {
-	err         error
 	conn        s3iface.S3API
 	region      string
 	bucket      string
@@ -84,6 +83,10 @@ func (s3sink *S3Sink) DeleteEntry(key string, isDirectory, deleteIncludeChunks b
 
 func (s3sink *S3Sink) CreateEntry(key string, entry *filer_pb.Entry) error {
 
+	if entry.IsDirectory {
+		return nil
+	}
+
 	uploadId, err := s3sink.createMultipartUpload(key, entry)
 	if err != nil {
 		return err