About
Snapshots support storing a copy of data at a particular instant of time. One usage of the snapshot feature may be to roll back a corrupted HDFS instance to a previously known good point in time.
Management
See Fsshell
Allow
See Dfsadmin option -allowSnapshot
<snapshotDir> : Allow snapshots to be taken on a directory.
==== Disallow ====
See Dfsadmin option -disallowSnapshot <snapshotDir> : Do not allow snapshots to be taken on a directory any more.
==== Diff ====
Hdfs diff sub-command make a diff of two snapshots of a directory or diff the current directory contents with a snapshot
<code>
hdfs snapshotDiff
</code>
==== List ====
list all snapshottable dirs owned by the current user
<code>hdfs lsSnapshottableDir
</code>
===== Documentation / Reference =====
* http://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsSnapshots.html