diff --git a/include/libs/sync/sync.h b/include/libs/sync/sync.h
index 5ffcbb7a09..b14b7667d2 100644
--- a/include/libs/sync/sync.h
+++ b/include/libs/sync/sync.h
@@ -98,8 +98,18 @@ typedef struct SSyncFSM {
 
   void (*FpRestoreFinishCb)(struct SSyncFSM* pFsm);
   int32_t (*FpGetSnapshot)(struct SSyncFSM* pFsm, SSnapshot* pSnapshot);
-  void* (*FpSnapshotRead)(struct SSyncFSM* pFsm, const SSnapshot* snapshot, void* iter, char** ppBuf, int32_t* len);
-  int32_t (*FpSnapshotApply)(struct SSyncFSM* pFsm, const SSnapshot* snapshot, char* pBuf, int32_t len);
+
+  // if (*ppIter == NULL)
+  //   *ppIter = new iter;
+  // else
+  //   *ppIter.next();
+  //
+  // if success, return 0. else return error code
+  int32_t (*FpSnapshotRead)(struct SSyncFSM* pFsm, const SSnapshot* pSnapshot, void** ppIter, char** ppBuf,
+                            int32_t* len);
+
+  // apply data into fsm
+  int32_t (*FpSnapshotApply)(struct SSyncFSM* pFsm, const SSnapshot* pSnapshot, char* pBuf, int32_t len);
 
   void (*FpReConfigCb)(struct SSyncFSM* pFsm, SSyncCfg newCfg, SReConfigCbMeta cbMeta);
 
diff --git a/source/dnode/mnode/impl/src/mndSync.c b/source/dnode/mnode/impl/src/mndSync.c
index f6b07fd880..47f11b652e 100644
--- a/source/dnode/mnode/impl/src/mndSync.c
+++ b/source/dnode/mnode/impl/src/mndSync.c
@@ -55,25 +55,33 @@ void mndRestoreFinish(struct SSyncFSM *pFsm) {
   }
 }
 
-void *mndSnapshotRead(struct SSyncFSM *pFsm, const SSnapshot *snapshot, void *iter, char **ppBuf, int32_t *len) {
-  SMnode   *pMnode = pFsm->data;
-  SSdbIter *pIter = iter;
-
-  if (iter == NULL) {
-    pIter = sdbIterInit(pMnode->pSdb);
+int32_t mndSnapshotRead(struct SSyncFSM* pFsm, const SSnapshot* pSnapshot, void** ppIter, char** ppBuf, int32_t* len) {
+  /*
+  SMnode *pMnode = pFsm->data;
+  SSdbIter *pIter;
+  if (iter == NULL) { 
+    pIter = sdbIterInit(pMnode->sdb)
+  } else {
+    pIter = iter;
   }
+  */
 
-  return sdbIterRead(pMnode->pSdb, pIter, ppBuf, len);
+  return 0;
 }
 
-int32_t mndSnapshotApply(struct SSyncFSM* pFsm, const SSnapshot* snapshot, char* pBuf, int32_t len) {
+int32_t mndSnapshotApply(struct SSyncFSM* pFsm, const SSnapshot* pSnapshot, char* pBuf, int32_t len) {
   SMnode *pMnode = pFsm->data;
   sdbWrite(pMnode->pSdb, (SSdbRaw*)pBuf);
   return 0;
 }
   
 void mndReConfig(struct SSyncFSM* pFsm, SSyncCfg newCfg, SReConfigCbMeta cbMeta) {
-
+  mInfo("mndReConfig cbMeta.code:%d, cbMeta.currentTerm:%ld, cbMeta.term:%ld, cbMeta.index:%ld", cbMeta.code, cbMeta.currentTerm, cbMeta.term, cbMeta.index);
+  if (cbMeta.code == 0) {
+    // config change success
+  } else {
+    // config change failed
+  }
 }
 
 SSyncFSM *mndSyncMakeFsm(SMnode *pMnode) {
diff --git a/source/libs/sync/src/syncAppendEntries.c b/source/libs/sync/src/syncAppendEntries.c
index 0411628c5c..c9e16c53c8 100644
--- a/source/libs/sync/src/syncAppendEntries.c
+++ b/source/libs/sync/src/syncAppendEntries.c
@@ -357,6 +357,16 @@ int32_t syncNodeOnAppendEntriesCb(SSyncNode* ths, SyncAppendEntries* pMsg) {
                 } else {
                   syncNodeBecomeFollower(ths);
                 }
+
+                // maybe newSyncCfg.myIndex is updated in syncNodeUpdateConfig
+                if (ths->pFsm->FpReConfigCb != NULL) {
+                  SReConfigCbMeta cbMeta = {0};
+                  cbMeta.code = 0;
+                  cbMeta.currentTerm = ths->pRaftStore->currentTerm;
+                  cbMeta.index = pEntry->index;
+                  cbMeta.term = pEntry->term;
+                  ths->pFsm->FpReConfigCb(ths->pFsm, newSyncCfg, cbMeta);
+                }
               }
 
               // restore finish
diff --git a/source/libs/sync/src/syncCommit.c b/source/libs/sync/src/syncCommit.c
index 36713ceed5..a3d480956e 100644
--- a/source/libs/sync/src/syncCommit.c
+++ b/source/libs/sync/src/syncCommit.c
@@ -134,6 +134,16 @@ void syncMaybeAdvanceCommitIndex(SSyncNode* pSyncNode) {
             } else {
               syncNodeBecomeFollower(pSyncNode);
             }
+
+            // maybe newSyncCfg.myIndex is updated in syncNodeUpdateConfig
+            if (pSyncNode->pFsm->FpReConfigCb != NULL) {
+              SReConfigCbMeta cbMeta = {0};
+              cbMeta.code = 0;
+              cbMeta.currentTerm = pSyncNode->pRaftStore->currentTerm;
+              cbMeta.index = pEntry->index;
+              cbMeta.term = pEntry->term;
+              pSyncNode->pFsm->FpReConfigCb(pSyncNode->pFsm, newSyncCfg, cbMeta);
+            }
           }
 
           // restore finish
diff --git a/source/libs/sync/src/syncMain.c b/source/libs/sync/src/syncMain.c
index 4aca68fa64..e4b6fc215f 100644
--- a/source/libs/sync/src/syncMain.c
+++ b/source/libs/sync/src/syncMain.c
@@ -349,7 +349,9 @@ int32_t syncPropose(int64_t rid, const SRpcMsg* pMsg, bool isWeak) {
 }
 
 // open/close --------------
-SSyncNode* syncNodeOpen(const SSyncInfo* pSyncInfo) {
+SSyncNode* syncNodeOpen(const SSyncInfo* pOldSyncInfo) {
+  SSyncInfo* pSyncInfo = (SSyncInfo*)pOldSyncInfo;
+
   SSyncNode* pSyncNode = (SSyncNode*)taosMemoryMalloc(sizeof(SSyncNode));
   assert(pSyncNode != NULL);
   memset(pSyncNode, 0, sizeof(SSyncNode));
@@ -361,11 +363,25 @@ SSyncNode* syncNodeOpen(const SSyncInfo* pSyncInfo) {
       sError("failed to create dir:%s since %s", pSyncInfo->path, terrstr());
       return NULL;
     }
+  }
 
+  snprintf(pSyncNode->configPath, sizeof(pSyncNode->configPath), "%s/raft_config.json", pSyncInfo->path);
+  if (!taosCheckExistFile(pSyncNode->configPath)) {
     // create raft config file
-    snprintf(pSyncNode->configPath, sizeof(pSyncNode->configPath), "%s/raft_config.json", pSyncInfo->path);
     ret = syncCfgCreateFile((SSyncCfg*)&(pSyncInfo->syncCfg), pSyncNode->configPath);
     assert(ret == 0);
+
+  } else {
+    // update syncCfg by raft_config.json
+    pSyncNode->pRaftCfg = raftCfgOpen(pSyncNode->configPath);
+    assert(pSyncNode->pRaftCfg != NULL);
+    pSyncInfo->syncCfg = pSyncNode->pRaftCfg->cfg;
+
+    char* seralized = raftCfg2Str(pSyncNode->pRaftCfg);
+    sInfo("syncNodeOpen update config :%s", seralized);
+    taosMemoryFree(seralized);
+
+    raftCfgClose(pSyncNode->pRaftCfg);
   }
 
   // init by SSyncInfo
diff --git a/source/libs/sync/test/syncTest.cpp b/source/libs/sync/test/syncTest.cpp
index 76024e061e..ffe8b81571 100644
--- a/source/libs/sync/test/syncTest.cpp
+++ b/source/libs/sync/test/syncTest.cpp
@@ -49,7 +49,7 @@ void test4() {
   logTest((char*)__FUNCTION__);
 }
 
-int main() {
+int main(int argc, char** argv) {
   // taosInitLog("tmp/syncTest.log", 100);
   tsAsyncLog = 0;
 
@@ -58,6 +58,14 @@ int main() {
   test3();
   test4();
 
+  if (argc == 2) {
+    bool bTaosDirExist = taosDirExist(argv[1]);
+    printf("%s bTaosDirExist:%d \n", argv[1], bTaosDirExist);
+
+    bool bTaosCheckExistFile = taosCheckExistFile(argv[1]);
+    printf("%s bTaosCheckExistFile:%d \n", argv[1], bTaosCheckExistFile);
+  }
+
   // taosCloseLog();
   return 0;
 }