diff --git a/src/tsdb/inc/tsdbFS.h b/src/tsdb/inc/tsdbFS.h
index 75567ef8c0d6da7bd062e9083db22a293ad2ef8e..281ee7dc682858a1f84e3affc3fb6457b090dc78 100644
--- a/src/tsdb/inc/tsdbFS.h
+++ b/src/tsdb/inc/tsdbFS.h
@@ -20,49 +20,62 @@
 extern "C" {
 #endif
 
+#define TSDB_FS_VERSION 0
+
+// ================== CURRENT file header info
+typedef struct {
+  uint32_t version;  // Current file version
+  uint32_t len;
+} SFSHeader;
+
+// ================== TSDB File System Meta
 typedef struct {
-  int64_t fsversion; // file system version, related to program
-  int64_t version;
-  int64_t totalPoints;
-  int64_t totalStorage;
+  uint64_t version;       // Commit version from 0 to increase
+  int64_t  totalPoints;   // total points
+  int64_t  totalStorage;  // Uncompressed total storage
 } STsdbFSMeta;
 
+// ==================
 typedef struct {
-  int64_t     version;
-  STsdbFSMeta meta;
-  SMFile      mf;  // meta file
-  SArray*     df;  // data file array
-} SFSVer;
+  STsdbFSMeta meta;  // FS meta
+  SMFile      mf;    // meta file
+  SArray*     df;    // data file array
+} SFSStatus;
 
 typedef struct {
   pthread_rwlock_t lock;
 
-  SFSVer fsv;
+  SFSStatus* cstatus;    // current stage
+  SHashObj*  metaCache;  // meta
+
+  bool       intxn;
+  SFSStatus* nstatus;
+  SList*     metaDelta;
 } STsdbFS;
 
+#define FS_CURRENT_STATUS(pfs) ((pfs)->cstatus)
+#define FS_NEW_STATUS(pfs) ((pfs)->nstatus)
+#define FS_IN_TXN(pfs) (pfs)->intxn
+
 typedef struct {
-  int        version;  // current FS version
+  uint64_t   version;  // current FS version
   int        index;
   int        fid;
   SDFileSet* pSet;
 } SFSIter;
 
+#if 0
 int        tsdbOpenFS(STsdbRepo* pRepo);
 void       tsdbCloseFS(STsdbRepo* pRepo);
 int        tsdbFSNewTxn(STsdbRepo* pRepo);
 int        tsdbFSEndTxn(STsdbRepo* pRepo, bool hasError);
 int        tsdbUpdateMFile(STsdbRepo* pRepo, SMFile* pMFile);
 int        tsdbUpdateDFileSet(STsdbRepo* pRepo, SDFileSet* pSet);
-void       tsdbRemoveExpiredDFileSet(STsdbRepo* pRepo, int mfid);
-int        tsdbRemoveDFileSet(SDFileSet* pSet);
-int        tsdbEncodeMFInfo(void** buf, SMFInfo* pInfo);
-void*      tsdbDecodeMFInfo(void* buf, SMFInfo* pInfo);
-SDFileSet  tsdbMoveDFileSet(SDFileSet* pOldSet, int to);
 int        tsdbInitFSIter(STsdbRepo* pRepo, SFSIter* pIter);
 SDFileSet* tsdbFSIterNext(SFSIter* pIter);
-int        tsdbCreateDFileSet(int fid, int level, SDFileSet* pSet);
+#endif
 
-static FORCE_INLINE int tsdbRLockFS(STsdbFS *pFs) {
+static FORCE_INLINE int tsdbRLockFS(STsdbFS* pFs) {
   int code = pthread_rwlock_rdlock(&(pFs->lock));
   if (code != 0) {
     terrno = TAOS_SYSTEM_ERROR(code);
@@ -71,7 +84,7 @@ static FORCE_INLINE int tsdbRLockFS(STsdbFS *pFs) {
   return 0;
 }
 
-static FORCE_INLINE int tsdbWLockFS(STsdbFS *pFs) {
+static FORCE_INLINE int tsdbWLockFS(STsdbFS* pFs) {
   int code = pthread_rwlock_wrlock(&(pFs->lock));
   if (code != 0) {
     terrno = TAOS_SYSTEM_ERROR(code);
@@ -80,7 +93,7 @@ static FORCE_INLINE int tsdbWLockFS(STsdbFS *pFs) {
   return 0;
 }
 
-static FORCE_INLINE int tsdbUnLockFS(STsdbFS *pFs) {
+static FORCE_INLINE int tsdbUnLockFS(STsdbFS* pFs) {
   int code = pthread_rwlock_unlock(&(pFs->lock));
   if (code != 0) {
     terrno = TAOS_SYSTEM_ERROR(code);
diff --git a/src/tsdb/inc/tsdbint.h b/src/tsdb/inc/tsdbint.h
index 48cb09cf80892d3755451897e50b0279d38a17a1..80360e89e1bcc52c6d74e3326430e1918ff3eee5 100644
--- a/src/tsdb/inc/tsdbint.h
+++ b/src/tsdb/inc/tsdbint.h
@@ -31,6 +31,7 @@
 #include "tchecksum.h"
 #include "tskiplist.h"
 #include "tdataformat.h"
+#include "tcoding.h"
 #include "tscompression.h"
 #include "tlockfree.h"
 #include "tlist.h"
@@ -85,6 +86,7 @@ struct STsdbRepo {
 
 #define REPO_ID(r) (r)->config.tsdbId
 #define REPO_CFG(r) (&((r)->config))
+#define REPO_FS(r) ((r)->fs)
 #define REPO_FS_VERSION(r)  // TODO
 #define IS_REPO_LOCKED(r) (r)->repoLocked
 #define TSDB_SUBMIT_MSG_HEAD_SIZE sizeof(SSubmitMsg)
diff --git a/src/tsdb/src/tsdbFS.c b/src/tsdb/src/tsdbFS.c
index 27ae452e545c10e8f47d4e8b03251222b6576223..7bdbe35c38517075eba2009f9837002e94cdd7b9 100644
--- a/src/tsdb/src/tsdbFS.c
+++ b/src/tsdb/src/tsdbFS.c
@@ -15,9 +15,236 @@
 
 #include "tsdbint.h"
 
-#define REPO_FS(r) ((r)->fs)
-#define TSDB_MAX_DFILES(keep, days) ((keep) / (days) + 3)
+#define TSDB_MAX_FSETS(keep, days) ((keep) / (days) + 3)
 
+// ================== CURRENT file header info
+static int tsdbEncodeFSHeader(void **buf, SFSHeader *pHeader) {
+  int tlen = 0;
+
+  tlen += taosEncodeFixedU32(buf, pHeader->version);
+  tlen += taosEncodeFixedU32(buf, pHeader->len);
+
+  return tlen;
+}
+
+static void *tsdbEncodeFSHeader(void *buf, SFSHeader *pHeader) {
+  buf = taosEncodeFixedU32(buf, &(pHeader->version));
+  buf = taosEncodeFixedU32(buf, &(pHeader->len));
+
+  return buf;
+}
+
+// ================== STsdbFSMeta
+static int tsdbEncodeFSMeta(void **buf, STsdbFSMeta *pMeta) {
+  int tlen = 0;
+
+  tlen += taosEncodeFixedU64(buf, pMeta->version);
+  tlen += taosEncodeFixedI64(buf, pMeta->totalPoints);
+  tlen += taosEncodeFixedI64(buf, pMeta->totalStorage);
+
+  return tlen;
+}
+
+static void *tsdbDecodeFSMeta(void *buf, STsdbFSMeta *pMeta) {
+  buf = taosDecodeFixedU64(buf, &(pMeta->version));
+  buf = taosDecodeFixedI64(buf, &(pMeta->totalPoints));
+  buf = taosDecodeFixedI64(buf, &(pMeta->totalStorage));
+
+  return buf;
+}
+
+// ================== SFSStatus
+static int tsdbEncodeDFileSetArray(void **buf, SArray *pArray) {
+  int      tlen = 0;
+  uint64_t nset = taosArrayGetSize(pArray);
+
+  tlen += taosEncodeFixedU64(buf, nset);
+  for (size_t i = 0; i < nset; i++) {
+    SDFileSet *pSet = taosArrayGet(pArray, i);
+
+    tlen += tsdbEncodeDFileSet(buf, pSet);
+  }
+
+  return tlen;
+}
+
+static int tsdbDecodeDFileSetArray(void *buf, SArray *pArray) {
+  uint64_t  nset;
+  SDFileSet dset;
+
+  taosArrayClear(pArray);
+
+  buf = taosDecodeFixedU64(buf, &nset);
+  for (size_t i = 0; i < nset; i++) {
+    SDFileSet *pSet = taosArrayGet(pArray, i);
+
+    buf = tsdbDecodeDFileSet(buf, &dset);
+    taosArrayPush(pArray, (void *)(&dset));
+  }
+  return buf;
+}
+
+static int tsdbEncodeFSStatus(void **buf, SFSStatus *pStatus) {
+  int tlen = 0;
+
+  tlen += tsdbEncodeFSMeta(buf, &(pStatus->meta));
+  tlen += tsdbEncodeSMFile(buf, &(pStatus->mf));
+  tlen += tsdbEncodeDFileSetArray(buf, pStatus->df);
+
+  return tlen;
+}
+
+static void *tsdbDecodeFSStatus(void *buf, SFSStatus *pStatus) {
+  buf = taosDecodeFixedU32(buf, pStatus->fsVer);
+  buf = tsdbDecodeFSMeta(buf, &(pStatus->meta));
+  buf = tsdbDecodeSMFile(buf, &(pStatus->mf));
+  buf = tsdbDecodeDFileSetArray(buf, pStatus->df);
+
+  return buf;
+}
+
+static SFSStatus *tsdbNewFSStatus(int maxFSet) {
+  SFSStatus *pStatus = (SFSStatus *)calloc(1, sizeof(*pStatus));
+  if (pStatus == NULL) {
+    terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+    return NULL;
+  }
+
+  pStatus->df = taosArrayInit(maxFSet, sizeof(SDFileSet));
+  if (pStatus->df) {
+    terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+    free(pStatus);
+    return NULL;
+  }
+
+  return pStatus;
+}
+
+static SFSStatus *tsdbFreeFSStatus(SFSStatus *pStatus) {
+  if (pStatus) {
+    pStatus->df = taosArrayDestroy(pStatus->df);
+    free(pStatus);
+  }
+
+  return NULL;
+}
+
+static void tsdbResetFSStatus(SFSStatus *pStatus) {
+  if (pStatus == NULL) {
+    return;
+  }
+
+  taosArrayClear(pStatus->df);
+}
+
+// ================== STsdbFS
+STsdbFS *tsdbNewFS(int maxFSet) {
+  STsdbFS *pFs = (STsdbFS *)calloc(1, sizeof(*pFs));
+  if (pFs == NULL) {
+    terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+    return NULL;
+  }
+
+  int code = pthread_rwlock_init(&(pFs->lock), NULL);
+  if (code) {
+    terrno = TAOS_SYSTEM_ERROR(code);
+    free(pFs);
+    return NULL;
+  }
+
+  pFs->cstatus = tsdbNewFSStatus(maxFSet);
+  if (pFs->cstatus == NULL) {
+    tsdbFreeFS(pFs);
+    return NULL;
+  }
+
+  pFs->metaCache = taosHashInit(4096, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), true, false);
+  if (pFs->metaCache == NULL) {
+    terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+    tsdbFreeFS(pFs);
+    return NULL;
+  }
+
+  pFs->nstatus = tsdbNewFSStatus(maxFSet);
+  if (pFs->nstatus == NULL) {
+    tsdbFreeFS(pFs);
+    return NULL;
+  }
+
+  pFs->metaDelta = tdListNew(sizeof(SKVRecord));
+  if (pFs->metaDelta == NULL) {
+    terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
+    tsdbFreeFS(pFs);
+    return NULL;
+  }
+
+  return NULL;
+}
+
+void *tsdbFreeFS(STsdbFS *pFs) {
+  if (pFs) {
+    pFs->metaDelta = tdListFree(pFs->metaDelta);
+    pFs->nstatus = tsdbFreeFSStatus(pFs->nstatus);
+    taosHashCleanup(pFs->metaCache);
+    pFs->metaCache = NULL;
+    pFs->cstatus = tsdbFreeFSStatus(pFs->cstatus);
+    pthread_rwlock_destroy(&(pFs->lock));
+  }
+  return NULL;
+}
+
+int tsdbOpenFS(STsdbFS *pFs, int keep, int days) {
+  // TODO
+
+  return 0;
+}
+
+void tsdbCloseFS(STsdbFS *pFs) {
+  // TODO
+}
+
+int tsdbStartTxn(STsdbFS *pFs) {
+  tsdbResetFSStatus(pFs->nstatus);
+  tdListEmpty(pFs->metaDelta);
+  return 0;
+}
+
+int tsdbEndTxn(STsdbFS *pFs, bool hasError) {
+  SFSStatus *pTStatus;
+
+  if (hasError) {
+    // TODO
+  } else {
+    // TODO 1. Create and open a new file current.t
+
+    // TODO 2. write new status to new file and fysnc and close
+
+    // TODO 3. rename current.t to current
+
+    // TODO 4. apply change to file
+    tsdbWLockFS(pFs);
+    pTStatus = pFs->cstatus;
+    pFs->cstatus = pFs->nstatus;
+    pFs->nstatus = pTStatus;
+    tsdbUnLockFS(pFs);
+
+    // TODO 5: apply meta change to cache
+  }
+
+  return 0;
+}
+
+// ================== SFSIter
+void tsdbFSIterInit(STsdbFS *pFs, SFSIter *pIter) {
+  // TODO
+}
+
+SDFileSet *tsdbFSIterNext(STsdbFS *pFs) {
+  // TODO
+  return NULL;
+}
+
+#if 0
 int tsdbOpenFS(STsdbRepo *pRepo) {
   ASSERT(REPO_FS == NULL);
 
@@ -85,7 +312,7 @@ int tsdbUpdateMFile(STsdbRepo *pRepo, SMFile *pMFile) {
 }
 
 int tsdbUpdateDFileSet(STsdbRepo *pRepo, SDFileSet *pSet) {
-  SFSVer *pSnapshot = REPO_FS(pRepo)->new;
+  SFSStatus *pSnapshot = REPO_FS(pRepo)->new;
   SDFileSet *  pOldSet;
 
   pOldSet = tsdbSearchDFileSet(pSnapshot, pSet->id, TD_GE);
@@ -113,7 +340,7 @@ int tsdbUpdateDFileSet(STsdbRepo *pRepo, SDFileSet *pSet) {
 }
 
 void tsdbRemoveExpiredDFileSet(STsdbRepo *pRepo, int mfid) {
-  SFSVer *pSnapshot = REPO_FS(pRepo)->new;
+  SFSStatus *pSnapshot = REPO_FS(pRepo)->new;
   while (taosArrayGetSize(pSnapshot->df) > 0) {
     SDFileSet *pSet = (SDFileSet *)taosArrayGet(pSnapshot->df, 0);
     if (pSet->id < mfid) {
@@ -137,17 +364,12 @@ SDFileSet *tsdbFSIterNext(SFSIter *pIter) {
   return NULL;
 }
 
-int tsdbCreateDFileSet(int fid, int level, SDFileSet *pSet) {
-  // TODO
-  return 0;
-}
-
-static int tsdbSaveFSSnapshot(int fd, SFSVer *pSnapshot) {
+static int tsdbSaveFSSnapshot(int fd, SFSStatus *pSnapshot) {
   // TODO
   return 0;
 }
 
-static int tsdbLoadFSSnapshot(SFSVer *pSnapshot) {
+static int tsdbLoadFSSnapshot(SFSStatus *pSnapshot) {
   // TODO
   return 0;
 }
@@ -190,7 +412,7 @@ static void *tsdbDecodeFSMeta(void *buf, STsdbFSMeta *pMeta) {
   return buf;
 }
 
-static int tsdbEncodeFSSnapshot(void **buf, SFSVer *pSnapshot) {
+static int tsdbEncodeFSSnapshot(void **buf, SFSStatus *pSnapshot) {
   int     tlen = 0;
   int64_t size = 0;
 
@@ -210,7 +432,7 @@ static int tsdbEncodeFSSnapshot(void **buf, SFSVer *pSnapshot) {
   return tlen;
 }
 
-static void *tsdbDecodeFSSnapshot(void *buf, SFSVer *pSnapshot) {
+static void *tsdbDecodeFSSnapshot(void *buf, SFSStatus *pSnapshot) {
   int64_t size = 0;
   SDFile  df;
 
@@ -227,10 +449,10 @@ static void *tsdbDecodeFSSnapshot(void *buf, SFSVer *pSnapshot) {
   return buf;
 }
 
-static SFSVer *tsdbNewSnapshot(int32_t nfiles) {
-  SFSVer *pSnapshot;
+static SFSStatus *tsdbNewSnapshot(int32_t nfiles) {
+  SFSStatus *pSnapshot;
 
-  pSnapshot = (SFSVer *)calloc(1, sizeof(pSnapshot));
+  pSnapshot = (SFSStatus *)calloc(1, sizeof(pSnapshot));
   if (pSnapshot == NULL) {
     terrno = TSDB_CODE_TDB_OUT_OF_MEMORY;
     return NULL;
@@ -246,7 +468,7 @@ static SFSVer *tsdbNewSnapshot(int32_t nfiles) {
   return pSnapshot;
 }
 
-static SFSVer *tsdbFreeSnapshot(SFSVer *pSnapshot) {
+static SFSStatus *tsdbFreeSnapshot(SFSStatus *pSnapshot) {
   if (pSnapshot) {
     taosArrayDestroy(pSnapshot->df);
     free(pSnapshot);
@@ -293,7 +515,7 @@ static STsdbFS *tsdbFreeFS(STsdbFS *pFs) {
   return NULL;
 }
 
-static int tsdbCopySnapshot(SFSVer *src, SFSVer *dst) {
+static int tsdbCopySnapshot(SFSStatus *src, SFSStatus *dst) {
   dst->meta = src->meta;
   dst->mf = src->meta;
   taosArrayCopy(dst->df, src->df);
@@ -313,7 +535,7 @@ static int tsdbCompFSetId(const void *key1, const void *key2) {
   }
 }
 
-static SDFileSet *tsdbSearchDFileSet(SFSVer *pSnapshot, int fid, int flags) {
+static SDFileSet *tsdbSearchDFileSet(SFSStatus *pSnapshot, int fid, int flags) {
   void *ptr = taosArraySearch(pSnapshot->df, (void *)(&fid), tsdbCompFSetId, flags);
   return (ptr == NULL) ? NULL : ((SDFileSet *)ptr);
 }
@@ -404,4 +626,5 @@ static int tsdbMakeFSDFileChange(STsdbRepo *pRepo) {
   }
 
   return 0;
-}
\ No newline at end of file
+}
+#endif
\ No newline at end of file
diff --git a/src/util/inc/tcoding.h b/src/util/inc/tcoding.h
index ff34c1560703a820b296911065c42e224fefcc03..636f9c5e50de40e3b311833515c5628de742c6a2 100644
--- a/src/util/inc/tcoding.h
+++ b/src/util/inc/tcoding.h
@@ -364,6 +364,15 @@ static FORCE_INLINE void *taosDecodeString(void *buf, char **value) {
   return POINTER_SHIFT(buf, size);
 }
 
+// ------ blank
+static FORCE_INLINE int taosEncodeBlank(void **buf, int nblank) {
+  // TODO
+}
+
+static FORCE_INLINE void *taosDecodeBlank(void *buf) {
+  // TODO
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/util/inc/tlist.h b/src/util/inc/tlist.h
index e8380294da47de1c9eb65059263ac820f3d816be..6c96ec0b138cfc229ab4a8bde3f3b374bce49dfd 100644
--- a/src/util/inc/tlist.h
+++ b/src/util/inc/tlist.h
@@ -47,7 +47,7 @@ typedef struct {
 #define listNodeFree(n) free(n);
 
 SList *    tdListNew(int eleSize);
-void       tdListFree(SList *list);
+void *     tdListFree(SList *list);
 void       tdListEmpty(SList *list);
 void       tdListPrependNode(SList *list, SListNode *node);
 void       tdListAppendNode(SList *list, SListNode *node);
diff --git a/src/util/src/tlist.c b/src/util/src/tlist.c
index 8c2ad83de117aaf528565a711a2aa3732984e0a9..2f52551e2ac7c79ef54cd4546be7bf844ff04980 100644
--- a/src/util/src/tlist.c
+++ b/src/util/src/tlist.c
@@ -38,11 +38,13 @@ void tdListEmpty(SList *list) {
   list->numOfEles = 0;
 }
 
-void tdListFree(SList *list) {
+void *tdListFree(SList *list) {
   if (list) {
     tdListEmpty(list);
     free(list);
   }
+
+  return NULL;
 }
 
 void tdListPrependNode(SList *list, SListNode *node) {