diff --git a/include/common/tmsg.h b/include/common/tmsg.h
index d69849349c..dcb3f54f47 100644
--- a/include/common/tmsg.h
+++ b/include/common/tmsg.h
@@ -1294,6 +1294,14 @@ typedef struct {
 int32_t tSerializeSDCreateMnodeReq(void* buf, int32_t bufLen, SDCreateMnodeReq* pReq);
 int32_t tDeserializeSDCreateMnodeReq(void* buf, int32_t bufLen, SDCreateMnodeReq* pReq);
 
+typedef struct {
+  int32_t dnodeId;
+  int8_t  standby;
+} SSetStandbyReq;
+
+int32_t tSerializeSSetStandbyReq(void* buf, int32_t bufLen, SSetStandbyReq* pReq);
+int32_t tDeserializeSSetStandbyReq(void* buf, int32_t bufLen, SSetStandbyReq* pReq);
+
 typedef struct {
   int32_t connId;
   int32_t queryId;
diff --git a/include/common/tmsgdef.h b/include/common/tmsgdef.h
index 743f10bd55..0f272aef9c 100644
--- a/include/common/tmsgdef.h
+++ b/include/common/tmsgdef.h
@@ -97,6 +97,7 @@ enum {
   TD_DEF_MSG_TYPE(TDMT_MND_CREATE_MNODE, "create-mnode", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_MND_ALTER_MNODE, "alter-mnode", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_MND_DROP_MNODE, "drop-mnode", NULL, NULL)
+  TD_DEF_MSG_TYPE(TDMT_MND_SET_STANDBY, "set-mnode-standby", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_MND_CREATE_QNODE, "create-qnode", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_MND_ALTER_QNODE, "alter-qnode", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_MND_DROP_QNODE, "drop-qnode", NULL, NULL)
diff --git a/source/common/src/tmsg.c b/source/common/src/tmsg.c
index d16ab57ea9..af8437e7c3 100644
--- a/source/common/src/tmsg.c
+++ b/source/common/src/tmsg.c
@@ -3506,6 +3506,33 @@ int32_t tDeserializeSDCreateMnodeReq(void *buf, int32_t bufLen, SDCreateMnodeReq
   return 0;
 }
 
+int32_t tSerializeSSetStandbyReq(void *buf, int32_t bufLen, SSetStandbyReq *pReq) {
+  SEncoder encoder = {0};
+  tEncoderInit(&encoder, buf, bufLen);
+
+  if (tStartEncode(&encoder) < 0) return -1;
+  if (tEncodeI32(&encoder, pReq->dnodeId) < 0) return -1;
+  if (tEncodeI8(&encoder, pReq->standby) < 0) return -1;
+  tEndEncode(&encoder);
+
+  int32_t tlen = encoder.pos;
+  tEncoderClear(&encoder);
+  return tlen;
+}
+
+int32_t tDeserializeSSetStandbyReq(void *buf, int32_t bufLen, SSetStandbyReq *pReq) {
+  SDecoder decoder = {0};
+  tDecoderInit(&decoder, buf, bufLen);
+
+  if (tStartDecode(&decoder) < 0) return -1;
+  if (tDecodeI32(&decoder, &pReq->dnodeId) < 0) return -1;
+  if (tDecodeI8(&decoder, &pReq->standby) < 0) return -1;
+  tEndDecode(&decoder);
+
+  tDecoderClear(&decoder);
+  return 0;
+}
+
 int32_t tSerializeSAuthReq(void *buf, int32_t bufLen, SAuthReq *pReq) {
   SEncoder encoder = {0};
   tEncoderInit(&encoder, buf, bufLen);
diff --git a/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c b/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c
index 2589bbd690..c47988e1ef 100644
--- a/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c
+++ b/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c
@@ -155,6 +155,7 @@ SArray *mmGetMsgHandles() {
   if (dmSetMgmtHandle(pArray, TDMT_MND_CREATE_MNODE, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_MND_ALTER_MNODE, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_MND_ALTER_MNODE_RSP, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
+  if (dmSetMgmtHandle(pArray, TDMT_MND_SET_STANDBY_RSP, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_MND_DROP_MNODE, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_MND_CREATE_QNODE, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_MND_DROP_QNODE, mmPutNodeMsgToWriteQueue, 0) == NULL) goto _OVER;
@@ -235,6 +236,7 @@ SArray *mmGetMsgHandles() {
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_APPEND_ENTRIES_REPLY, mmPutNodeMsgToSyncQueue, 1) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_SNAPSHOT_SEND, mmPutNodeMsgToSyncQueue, 1) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_SNAPSHOT_RSP, mmPutNodeMsgToSyncQueue, 1) == NULL) goto _OVER;
+  if (dmSetMgmtHandle(pArray, TDMT_MND_SET_STANDBY, mmPutNodeMsgToSyncQueue, 0) == NULL) goto _OVER;
 
   code = 0;
 
diff --git a/source/dnode/mnode/impl/src/mndMain.c b/source/dnode/mnode/impl/src/mndMain.c
index d8a61461dd..7a73d3c360 100644
--- a/source/dnode/mnode/impl/src/mndMain.c
+++ b/source/dnode/mnode/impl/src/mndMain.c
@@ -428,7 +428,6 @@ int32_t mndProcessSyncMsg(SRpcMsg *pMsg) {
       SyncClientRequest *pSyncMsg = syncClientRequestFromRpcMsg2(pMsg);
       code = syncNodeOnClientRequestCb(pSyncNode, pSyncMsg);
       syncClientRequestDestroy(pSyncMsg);
-
     } else if (pMsg->msgType == TDMT_SYNC_REQUEST_VOTE) {
       SyncRequestVote *pSyncMsg = syncRequestVoteFromRpcMsg2(pMsg);
       code = syncNodeOnRequestVoteSnapshotCb(pSyncNode, pSyncMsg);
@@ -445,7 +444,6 @@ int32_t mndProcessSyncMsg(SRpcMsg *pMsg) {
       SyncAppendEntriesReply *pSyncMsg = syncAppendEntriesReplyFromRpcMsg2(pMsg);
       code = syncNodeOnAppendEntriesReplySnapshotCb(pSyncNode, pSyncMsg);
       syncAppendEntriesReplyDestroy(pSyncMsg);
-
     } else if (pMsg->msgType == TDMT_SYNC_SNAPSHOT_SEND) {
       SyncSnapshotSend *pSyncMsg = syncSnapshotSendFromRpcMsg2(pMsg);
       code = syncNodeOnSnapshotSendCb(pSyncNode, pSyncMsg);
@@ -454,12 +452,14 @@ int32_t mndProcessSyncMsg(SRpcMsg *pMsg) {
       SyncSnapshotRsp *pSyncMsg = syncSnapshotRspFromRpcMsg2(pMsg);
       code = syncNodeOnSnapshotRspCb(pSyncNode, pSyncMsg);
       syncSnapshotRspDestroy(pSyncMsg);
-
+    } else if (pMsg->msgType == TDMT_MND_SET_STANDBY) {
+      code = syncSetStandby(pMgmt->sync);
+      SRpcMsg rsp = {.code = code, .info = pMsg->info};
+      tmsgSendRsp(&rsp);
     } else {
       mError("failed to process msg:%p since invalid type:%s", pMsg, TMSG_INFO(pMsg->msgType));
       code = TAOS_SYNC_PROPOSE_OTHER_ERROR;
     }
-
   } else {
     if (pMsg->msgType == TDMT_SYNC_TIMEOUT) {
       SyncTimeout *pSyncMsg = syncTimeoutFromRpcMsg2(pMsg);
@@ -493,6 +493,10 @@ int32_t mndProcessSyncMsg(SRpcMsg *pMsg) {
       SyncAppendEntriesReply *pSyncMsg = syncAppendEntriesReplyFromRpcMsg2(pMsg);
       code = syncNodeOnAppendEntriesReplyCb(pSyncNode, pSyncMsg);
       syncAppendEntriesReplyDestroy(pSyncMsg);
+    } else if (pMsg->msgType == TDMT_MND_SET_STANDBY) {
+      code = syncSetStandby(pMgmt->sync);
+      SRpcMsg rsp = {.code = code, .info = pMsg->info};
+      tmsgSendRsp(&rsp);
     } else {
       mError("failed to process msg:%p since invalid type:%s", pMsg, TMSG_INFO(pMsg->msgType));
       code = TAOS_SYNC_PROPOSE_OTHER_ERROR;
diff --git a/source/dnode/mnode/impl/src/mndMnode.c b/source/dnode/mnode/impl/src/mndMnode.c
index c5a4282b3b..95a2c3d935 100644
--- a/source/dnode/mnode/impl/src/mndMnode.c
+++ b/source/dnode/mnode/impl/src/mndMnode.c
@@ -55,6 +55,7 @@ int32_t mndInitMnode(SMnode *pMnode) {
   mndSetMsgHandle(pMnode, TDMT_MND_ALTER_MNODE_RSP, mndTransProcessRsp);
   mndSetMsgHandle(pMnode, TDMT_MND_DROP_MNODE, mndProcessDropMnodeReq);
   mndSetMsgHandle(pMnode, TDMT_DND_DROP_MNODE_RSP, mndTransProcessRsp);
+  mndSetMsgHandle(pMnode, TDMT_MND_SET_STANDBY_RSP, mndTransProcessRsp);
 
   mndAddShowRetrieveHandle(pMnode, TSDB_MGMT_TABLE_MNODE, mndRetrieveMnodes);
   mndAddShowFreeIterHandle(pMnode, TSDB_MGMT_TABLE_MNODE, mndCancelGetNextMnode);
@@ -460,6 +461,7 @@ static int32_t mndSetDropMnodeRedoActions(SMnode *pMnode, STrans *pTrans, SDnode
   int32_t         numOfReplicas = 0;
   SDAlterMnodeReq alterReq = {0};
   SDDropMnodeReq  dropReq = {0};
+  SSetStandbyReq  standbyReq = {0};
   SEpSet          alterEpset = {0};
   SEpSet          dropEpSet = {0};
 
@@ -494,6 +496,31 @@ static int32_t mndSetDropMnodeRedoActions(SMnode *pMnode, STrans *pTrans, SDnode
   dropEpSet.eps[0].port = pDnode->port;
   memcpy(dropEpSet.eps[0].fqdn, pDnode->fqdn, TSDB_FQDN_LEN);
 
+  standbyReq.dnodeId = pDnode->id;
+  standbyReq.standby = 1;
+
+  {
+    int32_t contLen = tSerializeSSetStandbyReq(NULL, 0, &standbyReq) + sizeof(SMsgHead);
+    void   *pReq = taosMemoryMalloc(contLen);
+    tSerializeSSetStandbyReq((char*)pReq + sizeof(SMsgHead), contLen, &standbyReq);
+    SMsgHead *pHead = pReq;
+    pHead->contLen = htonl(contLen);
+    pHead->vgId = htonl(MNODE_HANDLE);
+
+    STransAction action = {
+        .epSet = dropEpSet,
+        .pCont = pReq,
+        .contLen = contLen,
+        .msgType = TDMT_MND_SET_STANDBY,
+        .acceptableCode = TSDB_CODE_NODE_NOT_DEPLOYED,
+    };
+
+    if (mndTransAppendRedoAction(pTrans, &action) != 0) {
+      taosMemoryFree(pReq);
+      return -1;
+    }
+  }
+
   {
     int32_t contLen = tSerializeSDCreateMnodeReq(NULL, 0, &alterReq);
     void   *pReq = taosMemoryMalloc(contLen);
diff --git a/source/libs/sync/src/syncMain.c b/source/libs/sync/src/syncMain.c
index bd4d865ed2..e6aa8346b0 100644
--- a/source/libs/sync/src/syncMain.c
+++ b/source/libs/sync/src/syncMain.c
@@ -35,7 +35,7 @@
 #include "syncVoteMgr.h"
 #include "tref.h"
 
-bool gRaftDetailLog = false;
+bool gRaftDetailLog = true;
 
 static int32_t tsNodeRefId = -1;
 
@@ -152,7 +152,7 @@ int32_t syncSetStandby(int64_t rid) {
     return -1;
   }
 
-  if (pSyncNode->state != TAOS_SYNC_STATE_LEADER) {
+  if (pSyncNode->state == TAOS_SYNC_STATE_LEADER) {
     taosReleaseRef(tsNodeRefId, pSyncNode->rid);
     return -1;
   }
@@ -170,6 +170,7 @@ int32_t syncSetStandby(int64_t rid) {
   raftCfgPersist(pSyncNode->pRaftCfg);
 
   taosReleaseRef(tsNodeRefId, pSyncNode->rid);
+  sInfo("vgId:%d, set to standby", pSyncNode->vgId);
   return 0;
 }
 
@@ -1157,6 +1158,13 @@ void syncNodeUpdateConfig(SSyncNode* pSyncNode, SSyncCfg* newConfig, SyncIndex l
 
   int32_t ret = 0;
 
+  // save snapshot senders
+  int32_t oldReplicaNum = pSyncNode->replicaNum;
+  SRaftId oldReplicasId[TSDB_MAX_REPLICA];
+  memcpy(oldReplicasId, pSyncNode->replicasId, sizeof(oldReplicasId));
+  SSyncSnapshotSender*   oldSenders[TSDB_MAX_REPLICA];
+  memcpy(oldSenders, pSyncNode->senders, sizeof(oldSenders));
+
   // init internal
   pSyncNode->myNodeInfo = pSyncNode->pRaftCfg->cfg.nodeInfo[pSyncNode->pRaftCfg->cfg.myIndex];
   syncUtilnodeInfo2raftId(&pSyncNode->myNodeInfo, pSyncNode->vgId, &pSyncNode->myRaftId);
@@ -1187,6 +1195,27 @@ void syncNodeUpdateConfig(SSyncNode* pSyncNode, SSyncCfg* newConfig, SyncIndex l
 
   pSyncNode->quorum = syncUtilQuorum(pSyncNode->pRaftCfg->cfg.replicaNum);
 
+  // reset snapshot senders, memory leak
+  for (int i = 0; i < TSDB_MAX_REPLICA; ++i) {
+    (pSyncNode->senders)[i] = NULL;
+  }
+  for (int i = 0; i < pSyncNode->replicaNum; ++i) {
+    for (int j = 0; j < TSDB_MAX_REPLICA; ++j) {
+      if (syncUtilSameId(&(pSyncNode->replicasId)[i], &oldReplicasId[j])) {
+        char host[128];
+        uint16_t port;
+        syncUtilU642Addr((pSyncNode->replicasId)[i].addr, host, sizeof(host), &port);
+        sDebug("vgId:%d sync event reset sender for %lu, %s:%d", pSyncNode->vgId, (pSyncNode->replicasId)[i].addr, host, port);
+        (pSyncNode->senders)[i] = oldSenders[j];
+      }
+    }
+  }
+  for (int i = 0; i < TSDB_MAX_REPLICA; ++i) {
+    if ((pSyncNode->senders)[i] == NULL) {
+      (pSyncNode->senders)[i] = snapshotSenderCreate(pSyncNode, i);
+    }
+  }
+
   bool IamInOld = false;
   bool IamInNew = false;
   for (int i = 0; i < oldConfig.replicaNum; ++i) {
@@ -1845,7 +1874,8 @@ static int32_t syncNodeConfigChange(SSyncNode* ths, SRpcMsg* pRpcMsg, SSyncRaftE
 
   bool isDrop;
 
-  if (IamInNew || (!IamInNew && ths->state != TAOS_SYNC_STATE_LEADER)) {
+  //if (IamInNew || (!IamInNew && ths->state != TAOS_SYNC_STATE_LEADER)) {
+  if (IamInNew) {
     syncNodeUpdateConfig(ths, &newSyncCfg, pEntry->index, &isDrop);
 
     // change isStandBy to normal
@@ -1856,14 +1886,16 @@ static int32_t syncNodeConfigChange(SSyncNode* ths, SRpcMsg* pRpcMsg, SSyncRaftE
         syncNodeBecomeFollower(ths, "config change");
       }
     }
-
-    if (gRaftDetailLog) {
-      char* sOld = syncCfg2Str(&oldSyncCfg);
-      char* sNew = syncCfg2Str(&newSyncCfg);
-      sInfo("==config change== 0x11 old:%s new:%s isDrop:%d \n", sOld, sNew, isDrop);
-      taosMemoryFree(sOld);
-      taosMemoryFree(sNew);
-    }
+  } else {
+    syncNodeBecomeFollower(ths, "config change2");
+  }
+  
+  if (gRaftDetailLog) {
+    char* sOld = syncCfg2Str(&oldSyncCfg);
+    char* sNew = syncCfg2Str(&newSyncCfg);
+    sInfo("==config change== 0x11 old:%s new:%s isDrop:%d index:%ld \n", sOld, sNew, isDrop, pEntry->index);
+    taosMemoryFree(sOld);
+    taosMemoryFree(sNew);
   }
 
   // always call FpReConfigCb
diff --git a/source/libs/sync/src/syncSnapshot.c b/source/libs/sync/src/syncSnapshot.c
index 38742220fe..b8ed283170 100644
--- a/source/libs/sync/src/syncSnapshot.c
+++ b/source/libs/sync/src/syncSnapshot.c
@@ -755,6 +755,12 @@ int32_t syncNodeOnSnapshotSendCb(SSyncNode *pSyncNode, SyncSnapshotSend *pMsg) {
 // sender receives ack, set seq = ack + 1, send msg from seq
 // if ack == SYNC_SNAPSHOT_SEQ_END, stop sender
 int32_t syncNodeOnSnapshotRspCb(SSyncNode *pSyncNode, SyncSnapshotRsp *pMsg) {
+  // if already drop replica, do not process
+  if (!syncNodeInRaftGroup(pSyncNode, &(pMsg->srcId)) && pSyncNode->state == TAOS_SYNC_STATE_LEADER) {
+    sInfo("recv SyncSnapshotRsp maybe replica already dropped");
+    return 0;
+  }
+
   // get sender
   SSyncSnapshotSender *pSender = syncNodeGetSnapshotSender(pSyncNode, &(pMsg->srcId));
   ASSERT(pSender != NULL);
@@ -788,4 +794,4 @@ int32_t syncNodeOnSnapshotRspCb(SSyncNode *pSyncNode, SyncSnapshotRsp *pMsg) {
   }
 
   return 0;
-}
\ No newline at end of file
+}