diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 590dba01a3a40ac23ec38534425d90b47f197800..712ccbffbfba1a23b347a38008b1b381dc248698 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -7,6 +7,7 @@ ADD_SUBDIRECTORY(rpc)
 ADD_SUBDIRECTORY(client)
 ADD_SUBDIRECTORY(kit)
 ADD_SUBDIRECTORY(modules)
+ADD_SUBDIRECTORY(sdb)
 ADD_SUBDIRECTORY(mnode)
 ADD_SUBDIRECTORY(dnode)
 ADD_SUBDIRECTORY(vnode)
diff --git a/src/dnode/inc/dnodeMgmt.h b/src/dnode/inc/dnodeMgmt.h
index 51e3e7c18e315c9f1c8dac48786d2416b962d396..194bde30546d6c60bd10ae2e90f437f9cc5d31e3 100644
--- a/src/dnode/inc/dnodeMgmt.h
+++ b/src/dnode/inc/dnodeMgmt.h
@@ -21,14 +21,7 @@ extern "C" {
 #endif
 
 #include "tsched.h"
-
-typedef struct {
-  char  id[20];
-  char  sid;
-  void *thandle;
-  int   mgmtIndex;
-  char  status;  // 0:offline, 1:online
-} SMgmtObj;
+#include "dnode.h"
 
 int vnodeProcessCreateMeterRequest(char *pMsg, int msgLen, SMgmtObj *pMgmtObj);
 int vnodeProcessRemoveMeterRequest(char *pMsg, int msgLen, SMgmtObj *pMgmtObj);
@@ -37,24 +30,6 @@ void dnodeDistributeMsgFromMgmt(char *content, int msgLen, int msgType, SMgmtObj
 void mgmtProcessMsgFromDnodeSpec(SSchedMsg *sched);
 
 extern void *dmQhandle;
-extern char *(*taosBuildRspMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size);
-extern char *(*taosBuildReqMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size);
-extern char *(*taosBuildRspMsgToMnode)(SMgmtObj *pObj, char type);
-extern char *(*taosBuildReqMsgToMnode)(SMgmtObj *pObj, char type);
-extern int (*taosSendMsgToMnode)(SMgmtObj *pObj, char *msg, int msgLen);
-extern int (*taosSendSimpleRspToMnode)(SMgmtObj *pObj, char rsptype, char code);
-extern void (*dnodeInitMgmtIp)();
-extern int (*dnodeInitMgmtConn)();
-
-char *taosBuildRspMsgToMnodeWithSizeEdgeImp(SMgmtObj *pObj, char type, int size);
-char *taosBuildReqMsgToMnodeWithSizeEdgeImp(SMgmtObj *pObj, char type, int size);
-char *taosBuildRspMsgToMnodeEdgeImp(SMgmtObj *pObj, char type);
-char *taosBuildReqMsgToMnodeEdgeImp(SMgmtObj *pObj, char type);
-int taosSendMsgToMnodeEdgeImp(SMgmtObj *pObj, char *msg, int msgLen);
-int taosSendSimpleRspToMnodeEdgeImp(SMgmtObj *pObj, char rsptype, char code);
-void dnodeInitMgmtIpEdgeImp();
-void* dnodeProcessMsgFromMgmtEdgeImp(SSchedMsg *sched);
-int dnodeInitMgmtConnEdgeImp();
 
 #ifdef __cplusplus
 }
diff --git a/src/dnode/inc/dnodeService.h b/src/dnode/inc/dnodeService.h
deleted file mode 100644
index 66bcb2d8ad645d3462d0ed66210266105dd0206d..0000000000000000000000000000000000000000
--- a/src/dnode/inc/dnodeService.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
- *
- * This program is free software: you can use, redistribute, and/or modify
- * it under the terms of the GNU Affero General Public License, version 3
- * or later ("AGPL"), as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef TDENGINE_DNODE_SERVICE_H
-#define TDENGINE_DNODE_SERVICE_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif
diff --git a/src/dnode/src/dnodeMgmt.c b/src/dnode/src/dnodeMgmt.c
index 2a10e0a7469c385496a6c5c533c2a77b30679ce5..482e6ae477fea672719092c3a831026bb1c76e07 100644
--- a/src/dnode/src/dnodeMgmt.c
+++ b/src/dnode/src/dnodeMgmt.c
@@ -17,6 +17,7 @@
 
 #include "os.h"
 
+#include "dnode.h"
 #include "dnodeSystem.h"
 #include "dnodeMgmt.h"
 
@@ -43,17 +44,7 @@ void vnodeUpdateHeadFile(int vnode, int oldTables, int newTables);
 void vnodeOpenVnode(int vnode);
 void vnodeCleanUpOneVnode(int vnode);
 
-
-char *(*taosBuildRspMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size) = NULL;
-char *(*taosBuildReqMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size) = NULL;
-char *(*taosBuildRspMsgToMnode)(SMgmtObj *pObj, char type) = NULL;
-char *(*taosBuildReqMsgToMnode)(SMgmtObj *pObj, char type) = NULL;
-int (*taosSendMsgToMnode)(SMgmtObj *pObj, char *msg, int msgLen) = NULL;
-int (*taosSendSimpleRspToMnode)(SMgmtObj *pObj, char rsptype, char code) = NULL;
-void (*dnodeInitMgmtIp)() = NULL;
-int (*dnodeInitMgmtConn)() = NULL;
-
-char *taosBuildRspMsgToMnodeWithSizeEdgeImp(SMgmtObj *pObj, char type, int size) {
+char *taosBuildRspMsgToMnodeWithSizeImp(SMgmtObj *pObj, char type, int size) {
   char *pStart = (char *)malloc(size);
   if (pStart == NULL) {
     return NULL;
@@ -62,8 +53,9 @@ char *taosBuildRspMsgToMnodeWithSizeEdgeImp(SMgmtObj *pObj, char type, int size)
   *pStart = type;
   return pStart + 1;
 }
+char *(*taosBuildRspMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size) = taosBuildRspMsgToMnodeWithSizeImp;
 
-char *taosBuildReqMsgToMnodeWithSizeEdgeImp(SMgmtObj *pObj, char type, int size) {
+char *taosBuildReqMsgToMnodeWithSizeImp(SMgmtObj *pObj, char type, int size) {
   char *pStart = (char *)malloc(size);
   if (pStart == NULL) {
     return NULL;
@@ -72,16 +64,19 @@ char *taosBuildReqMsgToMnodeWithSizeEdgeImp(SMgmtObj *pObj, char type, int size)
   *pStart = type;
   return pStart + 1;
 }
+char *(*taosBuildReqMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size) = taosBuildReqMsgToMnodeWithSizeImp;
 
-char *taosBuildRspMsgToMnodeEdgeImp(SMgmtObj *pObj, char type) {
-  return taosBuildRspMsgToMnodeWithSize(pObj, type, 256);
+char *taosBuildRspMsgToMnodeImp(SMgmtObj *pObj, char type) {
+  return taosBuildRspMsgToMnodeWithSizeImp(pObj, type, 256);
 }
+char *(*taosBuildRspMsgToMnode)(SMgmtObj *pObj, char type) = taosBuildRspMsgToMnodeImp;
 
-char *taosBuildReqMsgToMnodeEdgeImp(SMgmtObj *pObj, char type) {
-  return taosBuildReqMsgToMnodeWithSize(pObj, type, 256);
+char *taosBuildReqMsgToMnodeImp(SMgmtObj *pObj, char type) {
+  return taosBuildReqMsgToMnodeWithSizeImp(pObj, type, 256);
 }
+char *(*taosBuildReqMsgToMnode)(SMgmtObj *pObj, char type) = taosBuildReqMsgToMnodeImp;
 
-int taosSendMsgToMnodeEdgeImp(SMgmtObj *pObj, char *msg, int msgLen) {
+int taosSendMsgToMnodeImp(SMgmtObj *pObj, char *msg, int msgLen) {
   dTrace("msg:%s is sent to mnode", taosMsg[(uint8_t)(*(msg-1))]);
 
   /*
@@ -96,8 +91,9 @@ int taosSendMsgToMnodeEdgeImp(SMgmtObj *pObj, char *msg, int msgLen) {
 
   return 0;
 }
+int (*taosSendMsgToMnode)(SMgmtObj *pObj, char *msg, int msgLen) = taosSendMsgToMnodeImp;
 
-int taosSendSimpleRspToMnodeEdgeImp(SMgmtObj *pObj, char rsptype, char code) {
+int taosSendSimpleRspToMnodeImp(SMgmtObj *pObj, char rsptype, char code) {
   char *pStart = taosBuildRspMsgToMnode(0, rsptype);
   if (pStart == NULL) {
     return 0;
@@ -108,8 +104,15 @@ int taosSendSimpleRspToMnodeEdgeImp(SMgmtObj *pObj, char rsptype, char code) {
 
   return 0;
 }
+int (*taosSendSimpleRspToMnode)(SMgmtObj *pObj, char rsptype, char code) = taosSendSimpleRspToMnodeImp;
+
+int32_t dnodeInitMgmtImp() { return 0; }
+int32_t (*dnodeInitMgmt)() = dnodeInitMgmtImp;
 
-void* dnodeProcessMsgFromMgmtEdgeImp(SSchedMsg *sched) {
+void dnodeInitMgmtIpImp() {}
+void (*dnodeInitMgmtIp)() = dnodeInitMgmtIpImp;
+
+void* dnodeProcessMsgFromMgmtImp(SSchedMsg *sched) {
   char  msgType = *sched->msg;
   char *content = sched->msg + 1;
 
@@ -122,13 +125,6 @@ void* dnodeProcessMsgFromMgmtEdgeImp(SSchedMsg *sched) {
   return NULL;
 }
 
-int dnodeInitMgmtConnEdgeImp() {
-  return 0;
-}
-
-void dnodeInitMgmtIpEdgeImp() {}
-
-
 void dnodeDistributeMsgFromMgmt(char *content, int msgLen, int msgType, SMgmtObj *pObj) {
   if (msgType == TSDB_MSG_TYPE_CREATE) {
     vnodeProcessCreateMeterRequest(content, msgLen, pObj);
diff --git a/src/dnode/src/dnodeModule.c b/src/dnode/src/dnodeModule.c
index c64aeb39c22700812e167ffa119b238f9a4ae7a2..5999ff3239461901e37619f05e0a9c5fa4219134 100644
--- a/src/dnode/src/dnodeModule.c
+++ b/src/dnode/src/dnodeModule.c
@@ -23,9 +23,6 @@
 #include "httpSystem.h"
 #include "mgmtSystem.h"
 
-#include "dcluster.h"
-#include "mstorage.h"
-
 SModule tsModule[TSDB_MOD_MAX] = {0};
 uint32_t tsModuleStatus = 0;
 
diff --git a/src/dnode/src/dnodeService.c b/src/dnode/src/dnodeService.c
index acf93b037e50366fabe1a456ed0824259f3ea2ae..9558052458ca7cdf632b577acc431ff669dee3dc 100644
--- a/src/dnode/src/dnodeService.c
+++ b/src/dnode/src/dnodeService.c
@@ -36,7 +36,7 @@
     mnodeAccountInit();
     mnodeBalanceInit();
     mnodeClusterInit();
-    mnodeReplicaInit();
+    sdbReplicaInit();
     multilevelStorageInit();
     vnodeClusterInit();
     vnodeReplicaInit();
diff --git a/src/dnode/src/dnodeSystem.c b/src/dnode/src/dnodeSystem.c
index 5d686c5dbe996d8425925ac7c8a3cad30a931105..7b2a273a14fb7cd2e700a20c1b435227d66221dd 100644
--- a/src/dnode/src/dnodeSystem.c
+++ b/src/dnode/src/dnodeSystem.c
@@ -21,7 +21,6 @@
 #include "dnode.h"
 #include "dnodeMgmt.h"
 #include "dnodeModule.h"
-#include "dnodeService.h"
 #include "dnodeSystem.h"
 #include "monitorSystem.h"
 #include "httpSystem.h"
@@ -43,14 +42,10 @@ void *   queryQhandle;
 int      tsVnodePeers = TSDB_VNODES_SUPPORT - 1;
 int      tsMaxQueues;
 uint32_t tsRebootTime;
-int    (*dnodeInitStorage)() = NULL;
-void   (*dnodeCleanupStorage)() = NULL;
-int    (*dnodeCheckSystem)() = NULL;
 
 int32_t dnodeInitRpcQHandle();
 int32_t dnodeInitQueryQHandle();
 int32_t dnodeInitTmrCtl();
-void dnodeInitPlugin();
 void dnodeCountRequestImp(SCountInfo *info);
 
 void dnodeCleanUpSystem() {
@@ -89,8 +84,6 @@ int dnodeInitSystem() {
   char        temp[128];
   struct stat dirstat;
 
-  dnodeInitPlugin();
-
   taosResolveCRC();
 
   tsRebootTime = taosGetTimestampSec();
@@ -170,7 +163,7 @@ int dnodeInitSystem() {
     return -1;
   }
 
-  if (dnodeInitMgmtConn() < 0) {
+  if (dnodeInitMgmt() < 0) {
     dError("failed to init communication to mgmt");
     return -1;
   }
@@ -208,7 +201,7 @@ void dnodeCountRequestImp(SCountInfo *info) {
   info->insertReqNum = atomic_exchange_32(&vnodeInsertReqNum, 0);
 }
 
-int dnodeInitStorageComImp() {
+int dnodeInitStorageImp() {
   struct stat dirstat;
   strcpy(tsDirectory, dataDir);
   if (stat(dataDir, &dirstat) < 0) {
@@ -229,8 +222,10 @@ int dnodeInitStorageComImp() {
 
   return 0;
 }
+int32_t (*dnodeInitStorage)() = dnodeInitStorageImp;
 
-void dnodeCleanupStorageComImp() {}
+void dnodeCleanupStorageImp() {}
+void (*dnodeCleanupStorage)() = dnodeCleanupStorageImp;
 
 int32_t dnodeInitQueryQHandle() {
   int numOfThreads = tsRatioOfQueryThreads * tsNumOfCores * tsNumOfThreadsPerCore;
@@ -271,24 +266,7 @@ int32_t dnodeInitRpcQHandle() {
 }
 
 
-int dnodeCheckSystemComImp() {
-  return 0;
-}
-
-void dnodeInitPlugin() {
-  dnodeInitMgmtConn = dnodeInitMgmtConnEdgeImp;
-  dnodeInitMgmtIp = dnodeInitMgmtIpEdgeImp;
-
-  taosBuildRspMsgToMnodeWithSize = taosBuildRspMsgToMnodeWithSizeEdgeImp;
-  taosBuildReqMsgToMnodeWithSize = taosBuildReqMsgToMnodeWithSizeEdgeImp;
-  taosBuildRspMsgToMnode = taosBuildRspMsgToMnodeEdgeImp;
-  taosBuildReqMsgToMnode = taosBuildReqMsgToMnodeEdgeImp;
-  taosSendMsgToMnode = taosSendMsgToMnodeEdgeImp;
-  taosSendSimpleRspToMnode = taosSendSimpleRspToMnodeEdgeImp;
-
-  dnodeCheckSystem = dnodeCheckSystemComImp;
-  dnodeInitStorage = dnodeInitStorageComImp;
-  dnodeCleanupStorage = dnodeCleanupStorageComImp;
-}
+int dnodeCheckSystemImp() { return 0; }
+int (*dnodeCheckSystem)() = dnodeCheckSystemImp;
 
 
diff --git a/src/inc/dnode.h b/src/inc/dnode.h
index e3d02470a56e417f468db7bd6d013ed93c626273..8da538d6e71e09b770282b192f03d7f40a810400 100644
--- a/src/inc/dnode.h
+++ b/src/inc/dnode.h
@@ -23,12 +23,30 @@ extern "C" {
 #include <stdint.h>
 #include <pthread.h>
 
+typedef struct {
+  char  id[20];
+  char  sid;
+  void *thandle;
+  int   mgmtIndex;
+  char  status;  // 0:offline, 1:online
+} SMgmtObj;
+
+// global variables
 extern pthread_mutex_t dmutex;
 
 // dnodeCluster
 extern void (*dnodeStartModules)();
 extern void (*dnodeParseParameterK)();
 extern int32_t (*dnodeCheckSystem)();
+extern char *(*taosBuildRspMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size);
+extern char *(*taosBuildReqMsgToMnodeWithSize)(SMgmtObj *pObj, char type, int size);
+extern char *(*taosBuildRspMsgToMnode)(SMgmtObj *pObj, char type);
+extern char *(*taosBuildReqMsgToMnode)(SMgmtObj *pObj, char type);
+extern int (*taosSendMsgToMnode)(SMgmtObj *pObj, char *msg, int msgLen);
+extern int (*taosSendSimpleRspToMnode)(SMgmtObj *pObj, char rsptype, char code);
+extern void (*dnodeInitMgmtIp)();
+extern int (*dnodeInitMgmt)();
+
 
 // multilevelStorage
 extern int32_t (*dnodeInitStorage)();
diff --git a/src/mnode/CMakeLists.txt b/src/mnode/CMakeLists.txt
index df4123d3c70a76e4d9dc318bfd17ed8790b5121d..ca14d807b6e00df345c8ed4210397b9603f45ff4 100644
--- a/src/mnode/CMakeLists.txt
+++ b/src/mnode/CMakeLists.txt
@@ -1,6 +1,5 @@
 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 PROJECT(TDengine)
 
-ADD_SUBDIRECTORY(sdb)
 ADD_SUBDIRECTORY(detail)
 ADD_SUBDIRECTORY(lite)
\ No newline at end of file
diff --git a/src/mnode/lite/src/mgmtDnodeInt.spec.c b/src/mnode/lite/src/mgmtDnodeInt.spec.c
index ab6b7fff3b6c690995b254b8373a79f46005e135..2de08c795a5e7471531b5740c0d80d5bcc42191e 100644
--- a/src/mnode/lite/src/mgmtDnodeInt.spec.c
+++ b/src/mnode/lite/src/mgmtDnodeInt.spec.c
@@ -28,7 +28,7 @@
 extern void *dmQhandle;
 void * mgmtStatusTimer = NULL;
 void   mgmtProcessMsgFromDnode(char *content, int msgLen, int msgType, SDnodeObj *pObj);
-void*   dnodeProcessMsgFromMgmtEdgeImp(SSchedMsg *sched);
+void*  dnodeProcessMsgFromMgmtImp(SSchedMsg *sched);
 
 char *taosBuildRspMsgToDnodeWithSize(SDnodeObj *pObj, char type, int size) {
   char *pStart = (char *)malloc(size);
@@ -67,7 +67,7 @@ int taosSendMsgToDnode(SDnodeObj *pObj, char *msg, int msgLen) {
    * Lite version has no message header, so minus one
    */
   SSchedMsg schedMsg;
-  schedMsg.fp = dnodeProcessMsgFromMgmtEdgeImp;
+  schedMsg.fp = dnodeProcessMsgFromMgmtImp;
   schedMsg.msg = msg - 1;
   schedMsg.ahandle = NULL;
   schedMsg.thandle = NULL;
diff --git a/src/mnode/sdb/CMakeLists.txt b/src/sdb/CMakeLists.txt
similarity index 100%
rename from src/mnode/sdb/CMakeLists.txt
rename to src/sdb/CMakeLists.txt
diff --git a/src/mnode/sdb/inc/hashint.h b/src/sdb/inc/hashint.h
similarity index 100%
rename from src/mnode/sdb/inc/hashint.h
rename to src/sdb/inc/hashint.h
diff --git a/src/mnode/sdb/inc/hashstr.h b/src/sdb/inc/hashstr.h
similarity index 100%
rename from src/mnode/sdb/inc/hashstr.h
rename to src/sdb/inc/hashstr.h
diff --git a/src/mnode/sdb/inc/sdbint.h b/src/sdb/inc/sdbint.h
similarity index 100%
rename from src/mnode/sdb/inc/sdbint.h
rename to src/sdb/inc/sdbint.h
diff --git a/src/mnode/sdb/src/hashint.c b/src/sdb/src/hashint.c
similarity index 100%
rename from src/mnode/sdb/src/hashint.c
rename to src/sdb/src/hashint.c
diff --git a/src/mnode/sdb/src/hashstr.c b/src/sdb/src/hashstr.c
similarity index 100%
rename from src/mnode/sdb/src/hashstr.c
rename to src/sdb/src/hashstr.c
diff --git a/src/mnode/sdb/src/sdbEngine.c b/src/sdb/src/sdbEngine.c
similarity index 100%
rename from src/mnode/sdb/src/sdbEngine.c
rename to src/sdb/src/sdbEngine.c
diff --git a/src/mnode/sdb/src/sdbstr.c b/src/sdb/src/sdbstr.c
similarity index 100%
rename from src/mnode/sdb/src/sdbstr.c
rename to src/sdb/src/sdbstr.c