diff --git a/source/dnode/mgmt/mgmt_vnode/src/vmFile.c b/source/dnode/mgmt/mgmt_vnode/src/vmFile.c
index 8337fb5d10..bf176ebb40 100644
--- a/source/dnode/mgmt/mgmt_vnode/src/vmFile.c
+++ b/source/dnode/mgmt/mgmt_vnode/src/vmFile.c
@@ -14,8 +14,8 @@
  */
 
 #define _DEFAULT_SOURCE
-#include "vmInt.h"
 #include "tjson.h"
+#include "vmInt.h"
 
 #define MAX_CONTENT_LEN 2 * 1024 * 1024
 
@@ -46,102 +46,108 @@ SVnodeObj **vmGetVnodeListFromHash(SVnodeMgmt *pMgmt, int32_t *numOfVnodes) {
   return pVnodes;
 }
 
-int32_t vmGetVnodeListFromFile(SVnodeMgmt *pMgmt, SWrapperCfg **ppCfgs, int32_t *numOfVnodes) {
-  int32_t      code = TSDB_CODE_INVALID_JSON_FORMAT;
-  int32_t      len = 0;
-  int32_t      maxLen = MAX_CONTENT_LEN;
-  char        *content = taosMemoryCalloc(1, maxLen + 1);
-  cJSON       *root = NULL;
-  FILE        *fp = NULL;
-  char         file[PATH_MAX] = {0};
+static int32_t vmDecodeVnodeList(SJson *pJson, SVnodeMgmt *pMgmt, SWrapperCfg **ppCfgs, int32_t *numOfVnodes) {
+  int32_t      code = -1;
   SWrapperCfg *pCfgs = NULL;
-  TdFilePtr    pFile = NULL;
+  *ppCfgs = NULL;
 
-  snprintf(file, sizeof(file), "%s%svnodes.json", pMgmt->path, TD_DIRSEP);
-
-  pFile = taosOpenFile(file, TD_FILE_READ);
-  if (pFile == NULL) {
-    dInfo("file %s not exist", file);
-    code = 0;
-    goto _OVER;
-  }
-
-  if (content == NULL) {
-    terrno = TSDB_CODE_OUT_OF_MEMORY;
-    return -1;
-  }
-
-  len = (int32_t)taosReadFile(pFile, content, maxLen);
-  if (len <= 0) {
-    dError("failed to read %s since content is null", file);
-    goto _OVER;
-  }
-
-  content[len] = 0;
-  root = cJSON_Parse(content);
-  if (root == NULL) {
-    dError("failed to read %s since invalid json format", file);
-    goto _OVER;
-  }
-
-  cJSON *vnodes = cJSON_GetObjectItem(root, "vnodes");
-  if (!vnodes || vnodes->type != cJSON_Array) {
-    dError("failed to read %s since vnodes not found", file);
-    goto _OVER;
-  }
+  SJson *vnodes = tjsonGetObjectItem(pJson, "vnodes");
+  if (vnodes == NULL) return -1;
 
   int32_t vnodesNum = cJSON_GetArraySize(vnodes);
   if (vnodesNum > 0) {
     pCfgs = taosMemoryCalloc(vnodesNum, sizeof(SWrapperCfg));
-    if (pCfgs == NULL) {
-      dError("failed to read %s since out of memory", file);
-      code = TSDB_CODE_OUT_OF_MEMORY;
-      goto _OVER;
-    }
-
-    for (int32_t i = 0; i < vnodesNum; ++i) {
-      cJSON       *vnode = cJSON_GetArrayItem(vnodes, i);
-      SWrapperCfg *pCfg = &pCfgs[i];
-
-      cJSON *vgId = cJSON_GetObjectItem(vnode, "vgId");
-      if (!vgId || vgId->type != cJSON_Number) {
-        dError("failed to read %s since vgId not found", file);
-        taosMemoryFree(pCfgs);
-        goto _OVER;
-      }
-      pCfg->vgId = vgId->valueint;
-      snprintf(pCfg->path, sizeof(pCfg->path), "%s%svnode%d", pMgmt->path, TD_DIRSEP, pCfg->vgId);
-
-      cJSON *dropped = cJSON_GetObjectItem(vnode, "dropped");
-      if (!dropped || dropped->type != cJSON_Number) {
-        dError("failed to read %s since dropped not found", file);
-        taosMemoryFree(pCfgs);
-        goto _OVER;
-      }
-      pCfg->dropped = dropped->valueint;
-
-      cJSON *vgVersion = cJSON_GetObjectItem(vnode, "vgVersion");
-      if (!vgVersion || vgVersion->type != cJSON_Number) {
-        dError("failed to read %s since vgVersion not found", file);
-        taosMemoryFree(pCfgs);
-        goto _OVER;
-      }
-      pCfg->vgVersion = vgVersion->valueint;
-    }
-
-    *ppCfgs = pCfgs;
+    if (pCfgs == NULL) return -1;
+  }
+
+  for (int32_t i = 0; i < vnodesNum; ++i) {
+    SJson *vnode = tjsonGetArrayItem(vnodes, i);
+    if (vnode == NULL) goto _OVER;
+
+    SWrapperCfg *pCfg = &pCfgs[i];
+    tjsonGetInt32ValueFromDouble(vnode, "vgId", pCfg->vgId, code);
+    if (code < 0) goto _OVER;
+    tjsonGetInt32ValueFromDouble(vnode, "dropped", pCfg->dropped, code);
+    if (code < 0) goto _OVER;
+    tjsonGetInt32ValueFromDouble(vnode, "vgVersion", pCfg->vgVersion, code);
+    if (code < 0) goto _OVER;
+
+    snprintf(pCfg->path, sizeof(pCfg->path), "%s%svnode%d", pMgmt->path, TD_DIRSEP, pCfg->vgId);
   }
 
-  *numOfVnodes = vnodesNum;
   code = 0;
-  dInfo("succcessed to read file %s, numOfVnodes:%d", file, vnodesNum);
+  *ppCfgs = pCfgs;
+  *numOfVnodes = vnodesNum;
 
 _OVER:
-  if (content != NULL) taosMemoryFree(content);
-  if (root != NULL) cJSON_Delete(root);
+  if (*ppCfgs == NULL) taosMemoryFree(pCfgs);
+  return code;
+}
+
+int32_t vmGetVnodeListFromFile(SVnodeMgmt *pMgmt, SWrapperCfg **ppCfgs, int32_t *numOfVnodes) {
+  int32_t      code = -1;
+  TdFilePtr    pFile = NULL;
+  char        *pData = NULL;
+  SJson       *pJson = NULL;
+  char         file[PATH_MAX] = {0};
+  SWrapperCfg *pCfgs = NULL;
+  snprintf(file, sizeof(file), "%s%svnodes.json", pMgmt->path, TD_DIRSEP);
+
+  if (taosStatFile(file, NULL, NULL) < 0) {
+    dInfo("vnode file:%s not exist", file);
+    return 0;
+  }
+
+  pFile = taosOpenFile(file, TD_FILE_READ);
+  if (pFile == NULL) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to open vnode file:%s since %s", file, terrstr());
+    goto _OVER;
+  }
+
+  int64_t size = 0;
+  if (taosFStatFile(pFile, &size, NULL) < 0) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to fstat mnode file:%s since %s", file, terrstr());
+    goto _OVER;
+  }
+
+  pData = taosMemoryMalloc(size + 1);
+  if (pData == NULL) {
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
+    goto _OVER;
+  }
+
+  if (taosReadFile(pFile, pData, size) != size) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to read vnode file:%s since %s", file, terrstr());
+    goto _OVER;
+  }
+
+  pData[size] = '\0';
+
+  pJson = tjsonParse(pData);
+  if (pJson == NULL) {
+    terrno = TSDB_CODE_INVALID_JSON_FORMAT;
+    goto _OVER;
+  }
+
+  if (vmDecodeVnodeList(pJson, pMgmt, ppCfgs, numOfVnodes) < 0) {
+    terrno = TSDB_CODE_INVALID_JSON_FORMAT;
+    goto _OVER;
+  }
+
+  code = 0;
+  dInfo("succceed to read vnode file %s", file);
+
+_OVER:
+  if (pData != NULL) taosMemoryFree(pData);
+  if (pJson != NULL) cJSON_Delete(pJson);
   if (pFile != NULL) taosCloseFile(&pFile);
 
-  terrno = code;
+  if (code != 0) {
+    dError("failed to read vnode file:%s since %s", file, terrstr());
+  }
   return code;
 }
 
diff --git a/source/dnode/mgmt/node_util/src/dmEps.c b/source/dnode/mgmt/node_util/src/dmEps.c
index 3e2d8b53aa..7bae703753 100644
--- a/source/dnode/mgmt/node_util/src/dmEps.c
+++ b/source/dnode/mgmt/node_util/src/dmEps.c
@@ -41,14 +41,49 @@ static void dmGetDnodeEp(SDnodeData *pData, int32_t dnodeId, char *pEp, char *pF
   taosThreadRwlockUnlock(&pData->lock);
 }
 
+static int32_t dmDecodeEps(SJson *pJson, SDnodeData *pData) {
+  int32_t code = 0;
+
+  tjsonGetInt32ValueFromDouble(pJson, "dnodeId", pData->dnodeId, code);
+  if (code < 0) return -1;
+  tjsonGetNumberValue(pJson, "dnodeVer", pData->dnodeVer, code);
+  if (code < 0) return -1;
+  tjsonGetNumberValue(pJson, "clusterId", pData->clusterId, code);
+  if (code < 0) return -1;
+  tjsonGetInt32ValueFromDouble(pJson, "dropped", pData->dropped, code);
+  if (code < 0) return -1;
+
+  SJson *dnodes = tjsonGetObjectItem(pJson, "dnodes");
+  if (dnodes == NULL) return 0;
+  int32_t numOfDnodes = tjsonGetArraySize(dnodes);
+
+  for (int32_t i = 0; i < numOfDnodes; ++i) {
+    SJson *dnode = tjsonGetArrayItem(dnodes, i);
+    if (dnode == NULL) return -1;
+
+    SDnodeEp dnodeEp = {0};
+    tjsonGetInt32ValueFromDouble(dnode, "id", dnodeEp.id, code);
+    if (code < 0) return -1;
+    code = tjsonGetStringValue(dnode, "fqdn", dnodeEp.ep.fqdn);
+    if (code < 0) return -1;
+    tjsonGetUInt16ValueFromDouble(dnode, "port", dnodeEp.ep.port, code);
+    if (code < 0) return -1;
+    tjsonGetInt8ValueFromDouble(dnode, "isMnode", dnodeEp.isMnode, code);
+    if (code < 0) return -1;
+
+    if (taosArrayPush(pData->dnodeEps, &dnodeEp) == NULL) return -1;
+  }
+
+  return 0;
+}
+
 int32_t dmReadEps(SDnodeData *pData) {
-  int32_t   code = TSDB_CODE_INVALID_JSON_FORMAT;
-  int32_t   len = 0;
-  int32_t   maxLen = 256 * 1024;
-  char     *content = taosMemoryCalloc(1, maxLen + 1);
-  cJSON    *root = NULL;
-  char      file[PATH_MAX] = {0};
+  int32_t   code = -1;
   TdFilePtr pFile = NULL;
+  char     *content = NULL;
+  SJson    *pJson = NULL;
+  char      file[PATH_MAX] = {0};
+  snprintf(file, sizeof(file), "%s%sdnode%sdnode.json", tsDataDir, TD_DIRSEP, TD_DIRSEP);
 
   pData->dnodeEps = taosArrayInit(1, sizeof(SDnodeEp));
   if (pData->dnodeEps == NULL) {
@@ -56,113 +91,63 @@ int32_t dmReadEps(SDnodeData *pData) {
     goto _OVER;
   }
 
-  snprintf(file, sizeof(file), "%s%sdnode%sdnode.json", tsDataDir, TD_DIRSEP, TD_DIRSEP);
-  pFile = taosOpenFile(file, TD_FILE_READ);
-  if (pFile == NULL) {
+  if (taosStatFile(file, NULL, NULL) < 0) {
+    dInfo("dnode file:%s not exist", file);
     code = 0;
     goto _OVER;
   }
 
-  len = (int32_t)taosReadFile(pFile, content, maxLen);
-  if (len <= 0) {
-    dError("failed to read %s since content is null", file);
+  pFile = taosOpenFile(file, TD_FILE_READ);
+  if (pFile == NULL) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to open dnode file:%s since %s", file, terrstr());
     goto _OVER;
   }
 
-  content[len] = 0;
-  root = cJSON_Parse(content);
-  if (root == NULL) {
-    dError("failed to read %s since invalid json format", file);
+  int64_t size = 0;
+  if (taosFStatFile(pFile, &size, NULL) < 0) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to fstat dnode file:%s since %s", file, terrstr());
     goto _OVER;
   }
 
-  cJSON *dnodeId = cJSON_GetObjectItem(root, "dnodeId");
-  if (!dnodeId || dnodeId->type != cJSON_Number) {
-    dError("failed to read %s since dnodeId not found", file);
-    goto _OVER;
-  }
-  pData->dnodeId = dnodeId->valueint;
-
-  cJSON *dnodeVer = cJSON_GetObjectItem(root, "dnodeVer");
-  if (!dnodeVer || dnodeVer->type != cJSON_String) {
-    dError("failed to read %s since dnodeVer not found", file);
-    goto _OVER;
-  }
-  pData->dnodeVer = atoll(dnodeVer->valuestring);
-
-  cJSON *clusterId = cJSON_GetObjectItem(root, "clusterId");
-  if (!clusterId || clusterId->type != cJSON_String) {
-    dError("failed to read %s since clusterId not found", file);
-    goto _OVER;
-  }
-  pData->clusterId = atoll(clusterId->valuestring);
-
-  cJSON *dropped = cJSON_GetObjectItem(root, "dropped");
-  if (!dropped || dropped->type != cJSON_Number) {
-    dError("failed to read %s since dropped not found", file);
-    goto _OVER;
-  }
-  pData->dropped = dropped->valueint;
-
-  cJSON *dnodes = cJSON_GetObjectItem(root, "dnodes");
-  if (!dnodes || dnodes->type != cJSON_Array) {
-    dError("failed to read %s since dnodes not found", file);
+  content = taosMemoryMalloc(size + 1);
+  if (content == NULL) {
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
     goto _OVER;
   }
 
-  int32_t numOfDnodes = cJSON_GetArraySize(dnodes);
-  if (numOfDnodes <= 0) {
-    dError("failed to read %s since numOfDnodes:%d invalid", file, numOfDnodes);
+  if (taosReadFile(pFile, content, size) != size) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to read dnode file:%s since %s", file, terrstr());
     goto _OVER;
   }
 
-  for (int32_t i = 0; i < numOfDnodes; ++i) {
-    cJSON *node = cJSON_GetArrayItem(dnodes, i);
-    if (node == NULL) break;
+  content[size] = '\0';
 
-    SDnodeEp dnodeEp = {0};
+  pJson = tjsonParse(content);
+  if (pJson == NULL) {
+    terrno = TSDB_CODE_INVALID_JSON_FORMAT;
+    goto _OVER;
+  }
 
-    cJSON *did = cJSON_GetObjectItem(node, "id");
-    if (!did || did->type != cJSON_Number) {
-      dError("failed to read %s since dnodeId not found", file);
-      goto _OVER;
-    }
-
-    dnodeEp.id = did->valueint;
-
-    cJSON *dnodeFqdn = cJSON_GetObjectItem(node, "fqdn");
-    if (!dnodeFqdn || dnodeFqdn->type != cJSON_String || dnodeFqdn->valuestring == NULL) {
-      dError("failed to read %s since dnodeFqdn not found", file);
-      goto _OVER;
-    }
-    tstrncpy(dnodeEp.ep.fqdn, dnodeFqdn->valuestring, TSDB_FQDN_LEN);
-
-    cJSON *dnodePort = cJSON_GetObjectItem(node, "port");
-    if (!dnodePort || dnodePort->type != cJSON_Number) {
-      dError("failed to read %s since dnodePort not found", file);
-      goto _OVER;
-    }
-
-    dnodeEp.ep.port = dnodePort->valueint;
-
-    cJSON *isMnode = cJSON_GetObjectItem(node, "isMnode");
-    if (!isMnode || isMnode->type != cJSON_Number) {
-      dError("failed to read %s since isMnode not found", file);
-      goto _OVER;
-    }
-    dnodeEp.isMnode = isMnode->valueint;
-
-    taosArrayPush(pData->dnodeEps, &dnodeEp);
+  if (dmDecodeEps(pJson, pData) < 0) {
+    terrno = TSDB_CODE_INVALID_JSON_FORMAT;
+    goto _OVER;
   }
 
   code = 0;
-  dDebug("succcessed to read file %s", file);
+  dInfo("succceed to read mnode file %s", file);
 
 _OVER:
   if (content != NULL) taosMemoryFree(content);
-  if (root != NULL) cJSON_Delete(root);
+  if (pJson != NULL) cJSON_Delete(pJson);
   if (pFile != NULL) taosCloseFile(&pFile);
 
+  if (code != 0) {
+    dError("failed to read dnode file:%s since %s", file, terrstr());
+  }
+
   if (taosArrayGetSize(pData->dnodeEps) == 0) {
     SDnodeEp dnodeEp = {0};
     dnodeEp.isMnode = 1;
@@ -178,7 +163,6 @@ _OVER:
     return -1;
   }
 
-  terrno = code;
   return code;
 }
 
@@ -247,7 +231,7 @@ _OVER:
 
   if (code != 0) {
     if (terrno == 0) terrno = TAOS_SYSTEM_ERROR(errno);
-    dInfo("succeed to write dnode file:%s since %s, dnodeVer:%" PRId64, realfile, terrstr(), pData->dnodeVer);
+    dError("failed to write dnode file:%s since %s, dnodeVer:%" PRId64, realfile, terrstr(), pData->dnodeVer);
   }
   return code;
 }
diff --git a/source/dnode/mgmt/node_util/src/dmFile.c b/source/dnode/mgmt/node_util/src/dmFile.c
index 4dcc962a20..fb05f08c0c 100644
--- a/source/dnode/mgmt/node_util/src/dmFile.c
+++ b/source/dnode/mgmt/node_util/src/dmFile.c
@@ -19,48 +19,81 @@
 
 #define MAXLEN 1024
 
-int32_t dmReadFile(const char *path, const char *name, bool *pDeployed) {
-  int32_t   code = TSDB_CODE_INVALID_JSON_FORMAT;
-  int64_t   len = 0;
-  char      content[MAXLEN + 1] = {0};
-  cJSON    *root = NULL;
-  char      file[PATH_MAX] = {0};
-  TdFilePtr pFile = NULL;
+static int32_t dmDecodeFile(SJson *pJson, bool *deployed) {
+  int32_t code = 0;
+  int32_t value = 0;
 
+  tjsonGetInt32ValueFromDouble(pJson, "deployed", value, code);
+  if (code < 0) return -1;
+
+  *deployed = (value != 0);
+  return code;
+}
+
+int32_t dmReadFile(const char *path, const char *name, bool *pDeployed) {
+  int32_t   code = -1;
+  TdFilePtr pFile = NULL;
+  char     *content = NULL;
+  SJson    *pJson = NULL;
+  char      file[PATH_MAX] = {0};
   snprintf(file, sizeof(file), "%s%s%s.json", path, TD_DIRSEP, name);
-  pFile = taosOpenFile(file, TD_FILE_READ);
-  if (pFile == NULL) {
+
+  if (taosStatFile(file, NULL, NULL) < 0) {
+    dInfo("file:%s not exist", file);
     code = 0;
     goto _OVER;
   }
 
-  len = taosReadFile(pFile, content, MAXLEN);
-  if (len <= 0) {
-    dError("failed to read %s since content is null", file);
+  pFile = taosOpenFile(file, TD_FILE_READ);
+  if (pFile == NULL) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to open file:%s since %s", file, terrstr());
     goto _OVER;
   }
 
-  root = cJSON_Parse(content);
-  if (root == NULL) {
-    dError("failed to read %s since invalid json format", file);
+  int64_t size = 0;
+  if (taosFStatFile(pFile, &size, NULL) < 0) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to fstat file:%s since %s", file, terrstr());
     goto _OVER;
   }
 
-  cJSON *deployed = cJSON_GetObjectItem(root, "deployed");
-  if (!deployed || deployed->type != cJSON_Number) {
-    dError("failed to read %s since deployed not found", file);
+  content = taosMemoryMalloc(size + 1);
+  if (content == NULL) {
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
+    goto _OVER;
+  }
+
+  if (taosReadFile(pFile, content, size) != size) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    dError("failed to read file:%s since %s", file, terrstr());
+    goto _OVER;
+  }
+
+  content[size] = '\0';
+
+  pJson = tjsonParse(content);
+  if (pJson == NULL) {
+    terrno = TSDB_CODE_INVALID_JSON_FORMAT;
+    goto _OVER;
+  }
+
+  if (dmDecodeFile(pJson, pDeployed) < 0) {
+    terrno = TSDB_CODE_INVALID_JSON_FORMAT;
     goto _OVER;
   }
-  *pDeployed = deployed->valueint != 0;
 
-  dDebug("succcessed to read file %s, deployed:%d", file, *pDeployed);
   code = 0;
+  dInfo("succceed to read mnode file %s", file);
 
 _OVER:
-  if (root != NULL) cJSON_Delete(root);
+  if (content != NULL) taosMemoryFree(content);
+  if (pJson != NULL) cJSON_Delete(pJson);
   if (pFile != NULL) taosCloseFile(&pFile);
 
-  terrno = code;
+  if (code != 0) {
+    dError("failed to read dnode file:%s since %s", file, terrstr());
+  }
   return code;
 }