HDFS - Snapshot

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1 - 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.

2 - Management

2.1 - Allow

See HDFS - DFSAdmin option -allowSnapshot <snapshotDir> : Allow snapshots to be taken on a directory.

2.2 - Disallow

See HDFS - DFSAdmin option -disallowSnapshot <snapshotDir> : Do not allow snapshots to be taken on a directory any more.

2.3 - Diff

HDFS - hdfs command line diff sub-command make a diff of two snapshots of a directory or diff the current directory contents with a snapshot

hdfs snapshotDiff         
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2.4 - List

list all snapshottable dirs owned by the current user

hdfs lsSnapshottableDir   

3 - Documentation / Reference