Checkpoints directory changed (#881)

* Update 3.manage-snapshot.md

checkpoints directory changed

* Update 3.manage-snapshot.md

docs-2.0/7.data-security/3.manage-snapshot.md

@@ -101,7 +101,11 @@ Currently, there is no command to restore data with snapshots. You need to manua
   SNAPSHOT_2021_03_09_09_10_52
   ```
 
-2. To restore the lost data through snapshots, users can take a snapshot at an appropriate time, copy the internal folders `data` and `wal` to their respective parent directories (at the same level with `checkpoints`), overwrite the previous `data` and `wal`, and then restart the cluster.
+2. To restore the lost data through snapshots, you can take a snapshot at an appropriate time, copy the folders `data` and `wal` in the corresponding snapshot directory to its parent directory (at the same level with `checkpoints`) to overwrite the previous `data` and `wal`, and then restart the cluster.
+
+  !!! caution
+
+        The data and wal directories of all Meta nodes should be overwritten at the same time. Otherwise, the new leader Meta node will use the latest Meta data after a cluster is restarted. 
 
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