diff --git a/weed/shell/command_ec_encode.go b/weed/shell/command_ec_encode.go
new file mode 100644
index 000000000..80a0ccf5c
--- /dev/null
+++ b/weed/shell/command_ec_encode.go
@@ -0,0 +1,78 @@
+package shell
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+
+	"github.com/chrislusf/seaweedfs/weed/operation"
+	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"google.golang.org/grpc"
+)
+
+func init() {
+	commands = append(commands, &commandEcEncode{})
+}
+
+type commandEcEncode struct {
+}
+
+func (c *commandEcEncode) Name() string {
+	return "ec.encode"
+}
+
+func (c *commandEcEncode) Help() string {
+	return `apply erasure coding to a volume
+
+	This command will:
+	1. freeze one volume
+	2. apply erasure coding to the volume
+	3. move the encoded shards to multiple volume servers
+
+	The erasure coding is 10.4. So ideally you have more than 14 volume servers, and you can afford
+	to lose 4 volume servers.
+
+	If the number of volumes are not high, the worst case is that you only have 4 volume servers,
+	and the shards are spread as 4,4,3,3, respectively. You can afford to lose one volume server.
+
+	If you only have less than 4 volume servers, with erasure coding, at least you can afford to
+	have 4 corrupted shard files.
+
+`
+}
+
+func (c *commandEcEncode) Do(args []string, commandEnv *commandEnv, writer io.Writer) (err error) {
+
+	encodeCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+	volumeId := encodeCommand.Int("vid", 0, "the volume id")
+	if err = encodeCommand.Parse(args); err != nil {
+		return nil
+	}
+
+	ctx := context.Background()
+
+	locations := commandEnv.masterClient.GetLocations(uint32(*volumeId))
+
+	if len(locations) == 0 {
+		return fmt.Errorf("volume %d not found", *volumeId)
+	}
+
+	err = generateEcSlices(ctx, commandEnv.option.GrpcDialOption, needle.VolumeId(*volumeId), locations[0].Url)
+
+	return err
+}
+
+func generateEcSlices(ctx context.Context, grpcDialOption grpc.DialOption, volumeId needle.VolumeId, sourceVolumeServer string) error {
+
+	err := operation.WithVolumeServerClient(sourceVolumeServer, grpcDialOption, func(volumeServerClient volume_server_pb.VolumeServerClient) error {
+		_, genErr := volumeServerClient.VolumeEcGenerateSlices(ctx, &volume_server_pb.VolumeEcGenerateSlicesRequest{
+			VolumeId: uint32(volumeId),
+		})
+		return genErr
+	})
+
+	return err
+
+}
diff --git a/weed/shell/command_volume_list.go b/weed/shell/command_volume_list.go
index ab6775f99..171f862c9 100644
--- a/weed/shell/command_volume_list.go
+++ b/weed/shell/command_volume_list.go
@@ -88,6 +88,9 @@ func writeDataNodeInfo(writer io.Writer, t *master_pb.DataNodeInfo) statistics {
 	for _, vi := range t.VolumeInfos {
 		s = s.plus(writeVolumeInformationMessage(writer, vi))
 	}
+	for _, ecShardInfo := range t.EcShardInfos {
+		fmt.Fprintf(writer, "        ec %+v \n", ecShardInfo)
+	}
 	fmt.Fprintf(writer, "      DataNode %s %+v \n", t.Id, s)
 	return s
 }
diff --git a/weed/storage/erasure_coding/ec_encoder.go b/weed/storage/erasure_coding/ec_encoder.go
index 54e757678..dbfe5858b 100644
--- a/weed/storage/erasure_coding/ec_encoder.go
+++ b/weed/storage/erasure_coding/ec_encoder.go
@@ -94,7 +94,7 @@ func encodeData(file *os.File, enc reedsolomon.Encoder, startOffset, blockSize i
 
 func openEcFiles(baseFileName string, forRead bool) (files []*os.File, err error) {
 	for i := 0; i < DataShardsCount+ParityShardsCount; i++ {
-		fname := baseFileName + ToExt(i+1)
+		fname := baseFileName + ToExt(i)
 		openOption := os.O_TRUNC | os.O_CREATE | os.O_WRONLY
 		if forRead {
 			openOption = os.O_RDONLY
diff --git a/weed/storage/erasure_coding/ec_volume_info.go b/weed/storage/erasure_coding/ec_volume_info.go
index 645686a92..cefc95173 100644
--- a/weed/storage/erasure_coding/ec_volume_info.go
+++ b/weed/storage/erasure_coding/ec_volume_info.go
@@ -1,6 +1,8 @@
 package erasure_coding
 
 import (
+	"fmt"
+
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
 	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
@@ -61,3 +63,7 @@ func (ecInfo *EcVolumeInfo) ToVolumeEcShardInformationMessage() (ret []*master_p
 	}
 	return
 }
+
+func (ecInfo *EcVolumeInfo) String() string {
+	return fmt.Sprintf("id:%d shard:%v collection:%v", ecInfo.VolumeId, ecInfo.ShardIds(), ecInfo.Collection)
+}
diff --git a/weed/topology/topology_ec.go b/weed/topology/topology_ec.go
index 8c8a0b67b..379440684 100644
--- a/weed/topology/topology_ec.go
+++ b/weed/topology/topology_ec.go
@@ -30,6 +30,7 @@ func (t *Topology) SyncDataNodeEcShards(shardInfos []*master_pb.VolumeEcShardInf
 			ecVolumeInfo = erasure_coding.NewEcVolumeInfo(shardInfo.Collection, needle.VolumeId(shardInfo.Id))
 			shards = append(shards, ecVolumeInfo)
 		}
+		prevVolumeId = shardInfo.Id
 		ecVolumeInfo.AddShardId(erasure_coding.ShardId(shardInfo.EcIndex))
 	}
 	// find out the delta volumes