diff --git a/weed/storage/erasure_coding/ec_volume_info.go b/weed/storage/erasure_coding/ec_volume_info.go
index 9cebb7d40..645686a92 100644
--- a/weed/storage/erasure_coding/ec_volume_info.go
+++ b/weed/storage/erasure_coding/ec_volume_info.go
@@ -40,6 +40,16 @@ func (ecInfo *EcVolumeInfo) ShardIds() (ret []ShardId) {
 	return
 }
 
+func (ecInfo *EcVolumeInfo) Minus(other *EcVolumeInfo) (*EcVolumeInfo) {
+	ret := &EcVolumeInfo{
+		VolumeId:   ecInfo.VolumeId,
+		Collection: ecInfo.Collection,
+		shardIds:   ecInfo.shardIds &^ other.shardIds,
+	}
+
+	return ret
+}
+
 func (ecInfo *EcVolumeInfo) ToVolumeEcShardInformationMessage() (ret []*master_pb.VolumeEcShardInformationMessage) {
 	for _, shard := range ecInfo.ShardIds() {
 		ret = append(ret, &master_pb.VolumeEcShardInformationMessage{
diff --git a/weed/topology/data_node_ec.go b/weed/topology/data_node_ec.go
index 5206a3b51..ef395dbdb 100644
--- a/weed/topology/data_node_ec.go
+++ b/weed/topology/data_node_ec.go
@@ -2,6 +2,7 @@ package topology
 
 import (
 	"github.com/chrislusf/seaweedfs/weed/storage/erasure_coding"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
 func (dn *DataNode) GetEcShards() (ret []*erasure_coding.EcVolumeInfo) {
@@ -14,7 +15,43 @@ func (dn *DataNode) GetEcShards() (ret []*erasure_coding.EcVolumeInfo) {
 }
 
 func (dn *DataNode) UpdateEcShards(actualShards []*erasure_coding.EcVolumeInfo) (newShards, deletedShards []*erasure_coding.EcVolumeInfo) {
-	dn.ecShardsLock.Lock()
-	dn.ecShardsLock.Unlock()
+	// prepare the new ec shard map
+	actualEcShardMap := make(map[needle.VolumeId]*erasure_coding.EcVolumeInfo)
+	for _, ecShards := range actualShards {
+		actualEcShardMap[ecShards.VolumeId]= ecShards
+	}
+
+	// found out the newShards and deletedShards
+	dn.ecShardsLock.RLock()
+	for vid, ecShards := range dn.ecShards{
+		if actualEcShards, ok := actualEcShardMap[vid]; !ok {
+			// dn registered ec shards not found in the new set of ec shards
+			deletedShards = append(deletedShards, ecShards)
+		} else {
+			// found, but maybe the actual shard could be missing
+			a := actualEcShards.Minus(ecShards)
+			if len(a.ShardIds())>0 {
+				newShards = append(newShards, a)
+			}
+			d := ecShards.Minus(actualEcShards)
+			if len(d.ShardIds())>0 {
+				deletedShards = append(deletedShards, d)
+			}
+		}
+	}
+	for _, ecShards := range actualShards {
+		if _, found := dn.ecShards[ecShards.VolumeId]; !found {
+			newShards = append(newShards, ecShards)
+		}
+	}
+	dn.ecShardsLock.RUnlock()
+
+	if len(newShards)>0 || len(deletedShards)>0{
+		// if changed, set to the new ec shard map
+		dn.ecShardsLock.Lock()
+		dn.ecShards = actualEcShardMap
+		dn.ecShardsLock.Unlock()
+	}
+
 	return
 }