Snapshot

Symptom:

If I creates a NAS volume and then a snap shot.  Then activate
the snap shot.  Now copy files to the volume and the snap shot percent
usage number goes up.  This seems to be wrong or is the snap shot
capturing all changes plus and minus?  It seems that deleted files from
the main NAS volume should be present but not added files etc.

Problem:

The snapshot uses copy-on-write on entire block devices by copying changed blocks—just
before they are to be overwritten—to other storage, thus preserving a self-consistent past
image of the block device.

Solution:

Do not use snapshot as a substitute for backup. As snapshots will only keep track of data
that changes

When you are adding new files to the volume, the snapshot is capturing empty blocks of
data. (those empty blocks are changing) If you delete or modify the files the snapshot
will capture the files being deleted.

Additional information:

Open-E software impacted:

Example ticket number:



Article ID: 153
Last updated: 25 Feb, 2009
Revision: 1
Information -> General info -> Snapshots -> Snapshot
https://kb.open-e.com/snapshot_153.html