diff --git a/source/common/src/tglobal.c b/source/common/src/tglobal.c
index 8d3deff495c32eb97fba80b71071f72baf9b3086..8823e63db4ab569c0dd55eb6488103897826a060 100644
--- a/source/common/src/tglobal.c
+++ b/source/common/src/tglobal.c
@@ -405,9 +405,8 @@ static int32_t taosAddServerCfg(SConfig *pCfg) {
   tsNumOfVnodeWriteThreads = TMAX(tsNumOfVnodeWriteThreads, 1);
   if (cfgAddInt32(pCfg, "numOfVnodeWriteThreads", tsNumOfVnodeWriteThreads, 1, 1024, 0) != 0) return -1;
 
-  // tsNumOfVnodeSyncThreads = tsNumOfCores;
-  tsNumOfVnodeSyncThreads = 32;
-  tsNumOfVnodeSyncThreads = TMAX(tsNumOfVnodeSyncThreads, 1);
+  tsNumOfVnodeSyncThreads = tsNumOfCores * 2;
+  tsNumOfVnodeSyncThreads = TMAX(tsNumOfVnodeSyncThreads, 16);
   if (cfgAddInt32(pCfg, "numOfVnodeSyncThreads", tsNumOfVnodeSyncThreads, 1, 1024, 0) != 0) return -1;
 
   tsNumOfQnodeQueryThreads = tsNumOfCores * 2;
diff --git a/source/libs/sync/inc/syncRaftCfg.h b/source/libs/sync/inc/syncRaftCfg.h
index fead7cdc762b46b4d3e26a2af0d5f370eb19c6cf..f0bfb883530287492f7bc44b22026f416ed4b6ed 100644
--- a/source/libs/sync/inc/syncRaftCfg.h
+++ b/source/libs/sync/inc/syncRaftCfg.h
@@ -31,6 +31,29 @@ extern "C" {
 
 #define MAX_CONFIG_INDEX_COUNT 512
 
+// SRaftCfgIndex ------------------------------------------
+typedef struct SRaftCfgIndex {
+  TdFilePtr pFile;
+  char      path[TSDB_FILENAME_LEN * 2];
+
+  SyncIndex configIndexArr[MAX_CONFIG_INDEX_COUNT];
+  int32_t   configIndexCount;
+} SRaftCfgIndex;
+
+SRaftCfgIndex *raftCfgIndexOpen(const char *path);
+int32_t        raftCfgIndexClose(SRaftCfgIndex *pRaftCfgIndex);
+int32_t        raftCfgIndexPersist(SRaftCfgIndex *pRaftCfgIndex);
+int32_t        raftCfgIndexAddConfigIndex(SRaftCfgIndex *pRaftCfgIndex, SyncIndex configIndex);
+
+cJSON  *raftCfgIndex2Json(SRaftCfgIndex *pRaftCfgIndex);
+char   *raftCfgIndex2Str(SRaftCfgIndex *pRaftCfgIndex);
+int32_t raftCfgIndexFromJson(const cJSON *pRoot, SRaftCfgIndex *pRaftCfgIndex);
+int32_t raftCfgIndexFromStr(const char *s, SRaftCfgIndex *pRaftCfgIndex);
+
+int32_t raftCfgIndexCreateFile(const char *path);
+
+// ---------------------------------------------------------
+
 typedef struct SRaftCfg {
   SSyncCfg  cfg;
   TdFilePtr pFile;
@@ -50,14 +73,14 @@ int32_t   raftCfgClose(SRaftCfg *pRaftCfg);
 int32_t   raftCfgPersist(SRaftCfg *pRaftCfg);
 int32_t   raftCfgAddConfigIndex(SRaftCfg *pRaftCfg, SyncIndex configIndex);
 
-cJSON * syncCfg2Json(SSyncCfg *pSyncCfg);
-char *  syncCfg2Str(SSyncCfg *pSyncCfg);
-char *  syncCfg2SimpleStr(SSyncCfg *pSyncCfg);
+cJSON  *syncCfg2Json(SSyncCfg *pSyncCfg);
+char   *syncCfg2Str(SSyncCfg *pSyncCfg);
+char   *syncCfg2SimpleStr(SSyncCfg *pSyncCfg);
 int32_t syncCfgFromJson(const cJSON *pRoot, SSyncCfg *pSyncCfg);
 int32_t syncCfgFromStr(const char *s, SSyncCfg *pSyncCfg);
 
-cJSON * raftCfg2Json(SRaftCfg *pRaftCfg);
-char *  raftCfg2Str(SRaftCfg *pRaftCfg);
+cJSON  *raftCfg2Json(SRaftCfg *pRaftCfg);
+char   *raftCfg2Str(SRaftCfg *pRaftCfg);
 int32_t raftCfgFromJson(const cJSON *pRoot, SRaftCfg *pRaftCfg);
 int32_t raftCfgFromStr(const char *s, SRaftCfg *pRaftCfg);
 
@@ -82,6 +105,11 @@ void raftCfgPrint2(char *s, SRaftCfg *pCfg);
 void raftCfgLog(SRaftCfg *pCfg);
 void raftCfgLog2(char *s, SRaftCfg *pCfg);
 
+void raftCfgIndexPrint(SRaftCfgIndex *pCfg);
+void raftCfgIndexPrint2(char *s, SRaftCfgIndex *pCfg);
+void raftCfgIndexLog(SRaftCfgIndex *pCfg);
+void raftCfgIndexLog2(char *s, SRaftCfgIndex *pCfg);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/sync/src/syncRaftCfg.c b/source/libs/sync/src/syncRaftCfg.c
index 56666b35b621d48d99c5a55063bd67c053d59776..5de21bceca99e13b3c2c33b72cd96f0ca6f86fa8 100644
--- a/source/libs/sync/src/syncRaftCfg.c
+++ b/source/libs/sync/src/syncRaftCfg.c
@@ -18,6 +18,149 @@
 #include "syncEnv.h"
 #include "syncUtil.h"
 
+// file must already exist!
+SRaftCfgIndex *raftCfgIndexOpen(const char *path) {
+  SRaftCfgIndex *pRaftCfgIndex = taosMemoryMalloc(sizeof(SRaftCfg));
+  snprintf(pRaftCfgIndex->path, sizeof(pRaftCfgIndex->path), "%s", path);
+
+  pRaftCfgIndex->pFile = taosOpenFile(pRaftCfgIndex->path, TD_FILE_READ | TD_FILE_WRITE);
+  ASSERT(pRaftCfgIndex->pFile != NULL);
+
+  taosLSeekFile(pRaftCfgIndex->pFile, 0, SEEK_SET);
+
+  int32_t bufLen = MAX_CONFIG_INDEX_COUNT * 16;
+  char   *pBuf = taosMemoryMalloc(bufLen);
+  memset(pBuf, 0, bufLen);
+  int64_t len = taosReadFile(pRaftCfgIndex->pFile, pBuf, bufLen);
+  ASSERT(len > 0);
+
+  int32_t ret = raftCfgIndexFromStr(pBuf, pRaftCfgIndex);
+  ASSERT(ret == 0);
+
+  taosMemoryFree(pBuf);
+
+  return pRaftCfgIndex;
+}
+
+int32_t raftCfgIndexClose(SRaftCfgIndex *pRaftCfgIndex) {
+  if (pRaftCfgIndex != NULL) {
+    int64_t ret = taosCloseFile(&(pRaftCfgIndex->pFile));
+    ASSERT(ret == 0);
+    taosMemoryFree(pRaftCfgIndex);
+  }
+  return 0;
+}
+
+int32_t raftCfgIndexPersist(SRaftCfgIndex *pRaftCfgIndex) {
+  ASSERT(pRaftCfgIndex != NULL);
+
+  char *s = raftCfgIndex2Str(pRaftCfgIndex);
+  taosLSeekFile(pRaftCfgIndex->pFile, 0, SEEK_SET);
+
+  int64_t ret = taosWriteFile(pRaftCfgIndex->pFile, s, strlen(s) + 1);
+  ASSERT(ret == strlen(s) + 1);
+
+  taosMemoryFree(s);
+  taosFsyncFile(pRaftCfgIndex->pFile);
+  return 0;
+}
+
+int32_t raftCfgIndexAddConfigIndex(SRaftCfgIndex *pRaftCfgIndex, SyncIndex configIndex) {
+  ASSERT(pRaftCfgIndex->configIndexCount <= MAX_CONFIG_INDEX_COUNT);
+  (pRaftCfgIndex->configIndexArr)[pRaftCfgIndex->configIndexCount] = configIndex;
+  ++(pRaftCfgIndex->configIndexCount);
+  return 0;
+}
+
+cJSON *raftCfgIndex2Json(SRaftCfgIndex *pRaftCfgIndex) {
+  cJSON *pRoot = cJSON_CreateObject();
+
+  cJSON_AddNumberToObject(pRoot, "configIndexCount", pRaftCfgIndex->configIndexCount);
+  cJSON *pIndexArr = cJSON_CreateArray();
+  cJSON_AddItemToObject(pRoot, "configIndexArr", pIndexArr);
+  for (int i = 0; i < pRaftCfgIndex->configIndexCount; ++i) {
+    char buf64[128];
+    snprintf(buf64, sizeof(buf64), "%" PRId64, (pRaftCfgIndex->configIndexArr)[i]);
+    cJSON *pIndexObj = cJSON_CreateObject();
+    cJSON_AddStringToObject(pIndexObj, "index", buf64);
+    cJSON_AddItemToArray(pIndexArr, pIndexObj);
+  }
+
+  cJSON *pJson = cJSON_CreateObject();
+  cJSON_AddItemToObject(pJson, "SRaftCfgIndex", pRoot);
+  return pJson;
+}
+
+char *raftCfgIndex2Str(SRaftCfgIndex *pRaftCfgIndex) {
+  cJSON *pJson = raftCfgIndex2Json(pRaftCfgIndex);
+  char  *serialized = cJSON_Print(pJson);
+  cJSON_Delete(pJson);
+  return serialized;
+}
+
+int32_t raftCfgIndexFromJson(const cJSON *pRoot, SRaftCfgIndex *pRaftCfgIndex) {
+  cJSON *pJson = cJSON_GetObjectItem(pRoot, "SRaftCfgIndex");
+
+  cJSON *pJsonConfigIndexCount = cJSON_GetObjectItem(pJson, "configIndexCount");
+  pRaftCfgIndex->configIndexCount = cJSON_GetNumberValue(pJsonConfigIndexCount);
+
+  cJSON *pIndexArr = cJSON_GetObjectItem(pJson, "configIndexArr");
+  int    arraySize = cJSON_GetArraySize(pIndexArr);
+  ASSERT(arraySize == pRaftCfgIndex->configIndexCount);
+
+  memset(pRaftCfgIndex->configIndexArr, 0, sizeof(pRaftCfgIndex->configIndexArr));
+  for (int i = 0; i < arraySize; ++i) {
+    cJSON *pIndexObj = cJSON_GetArrayItem(pIndexArr, i);
+    ASSERT(pIndexObj != NULL);
+
+    cJSON *pIndex = cJSON_GetObjectItem(pIndexObj, "index");
+    ASSERT(cJSON_IsString(pIndex));
+    (pRaftCfgIndex->configIndexArr)[i] = atoll(pIndex->valuestring);
+  }
+
+  return 0;
+}
+
+int32_t raftCfgIndexFromStr(const char *s, SRaftCfgIndex *pRaftCfgIndex) {
+  cJSON *pRoot = cJSON_Parse(s);
+  ASSERT(pRoot != NULL);
+
+  int32_t ret = raftCfgIndexFromJson(pRoot, pRaftCfgIndex);
+  ASSERT(ret == 0);
+
+  cJSON_Delete(pRoot);
+  return 0;
+}
+
+int32_t raftCfgIndexCreateFile(const char *path) {
+  TdFilePtr pFile = taosOpenFile(path, TD_FILE_CREATE | TD_FILE_WRITE);
+  if (pFile == NULL) {
+    int32_t     err = terrno;
+    const char *errStr = tstrerror(err);
+    int32_t     sysErr = errno;
+    const char *sysErrStr = strerror(errno);
+    sError("create raft cfg index file error, err:%d %X, msg:%s, syserr:%d, sysmsg:%s", err, err, errStr, sysErr,
+           sysErrStr);
+    ASSERT(0);
+
+    return -1;
+  }
+
+  SRaftCfgIndex raftCfgIndex;
+  memset(raftCfgIndex.configIndexArr, 0, sizeof(raftCfgIndex.configIndexArr));
+  raftCfgIndex.configIndexCount = 1;
+  raftCfgIndex.configIndexArr[0] = -1;
+
+  char   *s = raftCfgIndex2Str(&raftCfgIndex);
+  int64_t ret = taosWriteFile(pFile, s, strlen(s) + 1);
+  ASSERT(ret == strlen(s) + 1);
+
+  taosMemoryFree(s);
+  taosCloseFile(&pFile);
+  return 0;
+}
+
+// ---------------------------------------
 // file must already exist!
 SRaftCfg *raftCfgOpen(const char *path) {
   SRaftCfg *pCfg = taosMemoryMalloc(sizeof(SRaftCfg));
@@ -101,7 +244,7 @@ cJSON *syncCfg2Json(SSyncCfg *pSyncCfg) {
 
 char *syncCfg2Str(SSyncCfg *pSyncCfg) {
   cJSON *pJson = syncCfg2Json(pSyncCfg);
-  char * serialized = cJSON_Print(pJson);
+  char  *serialized = cJSON_Print(pJson);
   cJSON_Delete(pJson);
   return serialized;
 }
@@ -109,7 +252,7 @@ char *syncCfg2Str(SSyncCfg *pSyncCfg) {
 char *syncCfg2SimpleStr(SSyncCfg *pSyncCfg) {
   if (pSyncCfg != NULL) {
     int32_t len = 512;
-    char *  s = taosMemoryMalloc(len);
+    char   *s = taosMemoryMalloc(len);
     memset(s, 0, len);
 
     snprintf(s, len, "{r-num:%d, my:%d, ", pSyncCfg->replicaNum, pSyncCfg->myIndex);
@@ -206,7 +349,7 @@ cJSON *raftCfg2Json(SRaftCfg *pRaftCfg) {
 
 char *raftCfg2Str(SRaftCfg *pRaftCfg) {
   cJSON *pJson = raftCfg2Json(pRaftCfg);
-  char * serialized = cJSON_Print(pJson);
+  char  *serialized = cJSON_Print(pJson);
   cJSON_Delete(pJson);
   return serialized;
 }
@@ -285,7 +428,7 @@ int32_t raftCfgFromJson(const cJSON *pRoot, SRaftCfg *pRaftCfg) {
     (pRaftCfg->configIndexArr)[i] = atoll(pIndex->valuestring);
   }
 
-  cJSON * pJsonSyncCfg = cJSON_GetObjectItem(pJson, "SSyncCfg");
+  cJSON  *pJsonSyncCfg = cJSON_GetObjectItem(pJson, "SSyncCfg");
   int32_t code = syncCfgFromJson(pJsonSyncCfg, &(pRaftCfg->cfg));
   ASSERT(code == 0);
 
@@ -361,3 +504,30 @@ void raftCfgLog2(char *s, SRaftCfg *pCfg) {
   sTrace("raftCfgLog2 | len:%" PRIu64 " | %s | %s", strlen(serialized), s, serialized);
   taosMemoryFree(serialized);
 }
+
+// ---------
+void raftCfgIndexPrint(SRaftCfgIndex *pCfg) {
+  char *serialized = raftCfgIndex2Str(pCfg);
+  printf("raftCfgIndexPrint | len:%" PRIu64 " | %s \n", strlen(serialized), serialized);
+  fflush(NULL);
+  taosMemoryFree(serialized);
+}
+
+void raftCfgIndexPrint2(char *s, SRaftCfgIndex *pCfg) {
+  char *serialized = raftCfgIndex2Str(pCfg);
+  printf("raftCfgIndexPrint2 | len:%" PRIu64 " | %s | %s \n", strlen(serialized), s, serialized);
+  fflush(NULL);
+  taosMemoryFree(serialized);
+}
+
+void raftCfgIndexLog(SRaftCfgIndex *pCfg) {
+  char *serialized = raftCfgIndex2Str(pCfg);
+  sTrace("raftCfgIndexLog | len:%" PRIu64 " | %s", strlen(serialized), serialized);
+  taosMemoryFree(serialized);
+}
+
+void raftCfgIndexLog2(char *s, SRaftCfgIndex *pCfg) {
+  char *serialized = raftCfgIndex2Str(pCfg);
+  sTrace("raftCfgIndexLog2 | len:%" PRIu64 " | %s | %s", strlen(serialized), s, serialized);
+  taosMemoryFree(serialized);
+}
diff --git a/source/libs/sync/test/CMakeLists.txt b/source/libs/sync/test/CMakeLists.txt
index e787080795a36f77aca41d520ce7e232e9555358..72845d0c1d1a9378a3a189f4037c6fc646c8a536 100644
--- a/source/libs/sync/test/CMakeLists.txt
+++ b/source/libs/sync/test/CMakeLists.txt
@@ -56,6 +56,7 @@ add_executable(syncRaftLogTest3 "")
 add_executable(syncLeaderTransferTest "")
 add_executable(syncReconfigFinishTest "")
 add_executable(syncRestoreFromSnapshot "")
+add_executable(syncRaftCfgIndexTest "")
 
 
 target_sources(syncTest
@@ -290,6 +291,10 @@ target_sources(syncRestoreFromSnapshot
     PRIVATE
     "syncRestoreFromSnapshot.cpp"
 )
+target_sources(syncRaftCfgIndexTest
+    PRIVATE
+    "syncRaftCfgIndexTest.cpp"
+)
 
 
 target_include_directories(syncTest
@@ -582,6 +587,11 @@ target_include_directories(syncRestoreFromSnapshot
     "${TD_SOURCE_DIR}/include/libs/sync"
     "${CMAKE_CURRENT_SOURCE_DIR}/../inc"
 )
+target_include_directories(syncRaftCfgIndexTest
+    PUBLIC
+    "${TD_SOURCE_DIR}/include/libs/sync"
+    "${CMAKE_CURRENT_SOURCE_DIR}/../inc"
+)
 
 
 target_link_libraries(syncTest
@@ -816,6 +826,10 @@ target_link_libraries(syncRestoreFromSnapshot
     sync
     gtest_main
 )
+target_link_libraries(syncRaftCfgIndexTest
+    sync
+    gtest_main
+)
 
 
 enable_testing()
diff --git a/source/libs/sync/test/syncRaftCfgIndexTest.cpp b/source/libs/sync/test/syncRaftCfgIndexTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..6338383f92ceac88549753a415a5c7ba729c976f
--- /dev/null
+++ b/source/libs/sync/test/syncRaftCfgIndexTest.cpp
@@ -0,0 +1,96 @@
+#include "syncRaftStore.h"
+//#include <gtest/gtest.h>
+#include <stdio.h>
+#include "syncIO.h"
+#include "syncInt.h"
+#include "syncRaftCfg.h"
+#include "syncUtil.h"
+
+void logTest() {
+  sTrace("--- sync log test: trace");
+  sDebug("--- sync log test: debug");
+  sInfo("--- sync log test: info");
+  sWarn("--- sync log test: warn");
+  sError("--- sync log test: error");
+  sFatal("--- sync log test: fatal");
+}
+
+SRaftCfg* createRaftCfg() {
+  SRaftCfg* pCfg = (SRaftCfg*)taosMemoryMalloc(sizeof(SRaftCfg));
+  memset(pCfg, 0, sizeof(SRaftCfg));
+
+  pCfg->cfg.replicaNum = 3;
+  pCfg->cfg.myIndex = 1;
+  for (int i = 0; i < pCfg->cfg.replicaNum; ++i) {
+    ((pCfg->cfg.nodeInfo)[i]).nodePort = i * 100;
+    snprintf(((pCfg->cfg.nodeInfo)[i]).nodeFqdn, sizeof(((pCfg->cfg.nodeInfo)[i]).nodeFqdn), "100.200.300.%d", i);
+  }
+  pCfg->isStandBy = taosGetTimestampSec() % 100;
+  pCfg->batchSize = taosGetTimestampSec() % 100;
+
+  pCfg->configIndexCount = 5;
+  for (int i = 0; i < MAX_CONFIG_INDEX_COUNT; ++i) {
+    (pCfg->configIndexArr)[i] = -1;
+  }
+  for (int i = 0; i < pCfg->configIndexCount; ++i) {
+    (pCfg->configIndexArr)[i] = i * 100;
+  }
+
+  return pCfg;
+}
+
+SSyncCfg* createSyncCfg() {
+  SSyncCfg* pCfg = (SSyncCfg*)taosMemoryMalloc(sizeof(SSyncCfg));
+  memset(pCfg, 0, sizeof(SSyncCfg));
+
+  pCfg->replicaNum = 3;
+  pCfg->myIndex = 1;
+  for (int i = 0; i < pCfg->replicaNum; ++i) {
+    ((pCfg->nodeInfo)[i]).nodePort = i * 100;
+    snprintf(((pCfg->nodeInfo)[i]).nodeFqdn, sizeof(((pCfg->nodeInfo)[i]).nodeFqdn), "100.200.300.%d", i);
+  }
+
+  return pCfg;
+}
+
+const char *pFile = "./raft_config_index.json";
+
+void test1() {
+  int32_t code = raftCfgIndexCreateFile(pFile);
+  ASSERT(code == 0);
+
+  SRaftCfgIndex *pRaftCfgIndex = raftCfgIndexOpen(pFile);
+  raftCfgIndexLog2((char*)"==test1==", pRaftCfgIndex);
+
+  raftCfgIndexClose(pRaftCfgIndex);
+}
+
+void test2() {
+  SRaftCfgIndex *pRaftCfgIndex = raftCfgIndexOpen(pFile);
+  for (int i = 0; i < 500; ++i) {
+    raftCfgIndexAddConfigIndex(pRaftCfgIndex, i);
+  }
+  raftCfgIndexPersist(pRaftCfgIndex);
+
+  raftCfgIndexLog2((char*)"==test2==", pRaftCfgIndex);
+  raftCfgIndexClose(pRaftCfgIndex);
+}
+
+void test3() {
+  SRaftCfgIndex *pRaftCfgIndex = raftCfgIndexOpen(pFile);
+
+  raftCfgIndexLog2((char*)"==test3==", pRaftCfgIndex);
+  raftCfgIndexClose(pRaftCfgIndex);
+}
+
+int main() {
+  tsAsyncLog = 0;
+  sDebugFlag = DEBUG_TRACE + DEBUG_SCREEN + DEBUG_FILE;
+
+  logTest();
+  test1();
+  test2();
+  test3();
+
+  return 0;
+}