diff --git a/CMakeLists.txt b/CMakeLists.txt
index 588526c28614f753f6ff70e898f13f3fd65318db..d96c8da57715631344a971caa30bd81c6fdbcb4f 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,6 +16,7 @@ SET(TD_GRANT FALSE)
 SET(TD_SYNC TRUE)
 SET(TD_MQTT TRUE)
 SET(TD_TSDB_PLUGINS FALSE)
+SET(TD_DNODE_PLUGINS FALSE)
 
 SET(TD_COVER FALSE)
 SET(TD_MEM_CHECK FALSE)
diff --git a/cmake/define.inc b/cmake/define.inc
index 6e64c2709abee366856a61916c6905363ea2002d..3bd1520065f886a56b95f89875fac7977bc396ce 100755
--- a/cmake/define.inc
+++ b/cmake/define.inc
@@ -25,6 +25,10 @@ IF (TD_TSDB_PLUGINS)
   ADD_DEFINITIONS(-D_TSDB_PLUGINS)
 ENDIF ()
 
+IF (TD_DNODE_PLUGINS)
+  ADD_DEFINITIONS(-D_DNODE_PLUGINS)
+ENDIF ()
+
 IF (TD_GODLL)
   ADD_DEFINITIONS(-D_TD_GO_DLL_)
 ENDIF ()
diff --git a/src/dnode/inc/dnodeTier.h b/src/dnode/inc/dnodeTier.h
new file mode 100644
index 0000000000000000000000000000000000000000..019a4a21121eba0ded46d9730c3068c56784728d
--- /dev/null
+++ b/src/dnode/inc/dnodeTier.h
@@ -0,0 +1,107 @@
+/*
+ * 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_TIER_H
+#define TDENGINE_DNODE_TIER_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "hash.h"
+#include "taoserror.h"
+
+#define DNODE_MAX_TIERS 3
+#define DNODE_MAX_DISKS_PER_TIER 16
+
+typedef struct {
+  int level;
+  int did;
+} SDiskID;
+
+typedef struct {
+  uint64_t size;
+  uint64_t free;
+  uint64_t nfiles;
+} SDiskMeta;
+
+typedef struct {
+  char      dir[TSDB_FILENAME_LEN];
+  SDiskMeta dmeta;
+} SDisk;
+
+typedef struct {
+  int   level;
+  int   nDisks;
+  SDisk disks[DNODE_MAX_DISKS_PER_TIER];
+} STier;
+
+typedef struct {
+  pthread_rwlock_t rwlock;
+  int              nTiers;
+  STier            tiers[DNODE_MAX_TIERS];
+  SHashObj *       map;
+} SDnodeTier;
+
+#define DNODE_PRIMARY_DISK(pDnodeTier) (&(pDnodeTier)->tiers[0].disks[0])
+
+static FORCE_INLINE int dnodeRLockTiers(SDnodeTier *pDnodeTier) {
+  int code = pthread_rwlock_rdlock(&(pDnodeTier->rwlock));
+  if (code != 0) {
+    terrno = TAOS_SYSTEM_ERROR(code);
+    return -1;
+  }
+  return 0;
+}
+
+static FORCE_INLINE int dnodeWLockTiers(SDnodeTier *pDnodeTier) {
+  int code = pthread_rwlock_wrlock(&(pDnodeTier->rwlock));
+  if (code != 0) {
+    terrno = TAOS_SYSTEM_ERROR(code);
+    return -1;
+  }
+  return 0;
+}
+
+static FORCE_INLINE int dnodeUnLockTiers(SDnodeTier *pDnodeTier) {
+  int code = pthread_rwlock_unlock(&(pDnodeTier->rwlock));
+  if (code != 0) {
+    terrno = TAOS_SYSTEM_ERROR(code);
+    return -1;
+  }
+  return 0;
+}
+
+static FORCE_INLINE SDisk *dnodeGetDisk(SDnodeTier *pDnodeTier, int level, int did) {
+  if (level < 0 || level >= pDnodeTier->nTiers) return NULL;
+
+  if (did < 0 || did >= pDnodeTier->tiers[level].nDisks) return NULL;
+
+  return &(pDnodeTier->tiers[level].disks[did]);
+}
+
+SDnodeTier *dnodeNewTier();
+void *      dnodeCloseTier(SDnodeTier *pDnodeTier);
+int         dnodeAddDisk(SDnodeTier *pDnodeTier, char *dir, int level);
+int         dnodeUpdateTiersInfo(SDnodeTier *pDnodeTier);
+int         dnodeCheckTiers(SDnodeTier *pDnodeTier);
+SDisk *     dnodeAssignDisk(SDnodeTier *pDnodeTier, int level);
+SDisk *     dnodeGetDiskByName(SDnodeTier *pDnodeTier, char *dirName);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/src/dnode/src/dnodeTier.c b/src/dnode/src/dnodeTier.c
new file mode 100644
index 0000000000000000000000000000000000000000..0bd1a38911661a7a9781662d5e971ba2ad24ce2e
--- /dev/null
+++ b/src/dnode/src/dnodeTier.c
@@ -0,0 +1,29 @@
+/*
+ * 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/>.
+ */
+
+#include "os.h"
+#include "dnodeTier.h"
+
+#ifndef _DNODE_PLUGINS
+
+SDnodeTier *dnodeNewTier() { return NULL; }
+void *      dnodeCloseTier(SDnodeTier *pDnodeTier) { return NULL; }
+int         dnodeAddDisk(SDnodeTier *pDnodeTier, char *dir, int level) { return 0; }
+int         dnodeUpdateTiersInfo(SDnodeTier *pDnodeTier) { return 0; }
+int         dnodeCheckTiers(SDnodeTier *pDnodeTier) { return 0; }
+SDisk *     dnodeAssignDisk(SDnodeTier *pDnodeTier, int level) { return NULL; }
+SDisk *     dnodeGetDiskByName(SDnodeTier *pDnodeTier, char *dirName) { return NULL; }
+
+#endif
\ No newline at end of file