A snapshot is a consistent, point-in-time image of the contents of the backup destination.
Continuous backup jobs use a filter driver to capture changed bytes in the data files on the source and move the changed bytes to the backup destination whenever the information changes. CPS takes snapshots of the backup destination at scheduled intervals.
Administrators schedule snapshots based on the importance of the data being backed up. Users can then select the specific versions of files to retrieve. The latest files on the backup destination can also be restored, although the latest version might not have been captured in a snapshot.
Administrators define retention policies to save snapshots for specific periods of time. When the snapshot expires, it is removed automatically. If the destination reaches the limit of its disk space, the oldest snapshot is overwritten by new snapshots. In addition, a history of the snapshots can be viewed and unnecessary snapshots can be manually deleted from within the CPS Administration Console. However, when snapshots are deleted, the disk space may not be immediately freed.
Additional details about managing snapshots include the following:
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Snapshots can be stored up to a limit that is determined by the underlying snapshot technology. This limit may vary considerably if alternative snapshot providers are installed.
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Snapshots that are scheduled to be taken over a period of time where the end time is earlier than the start time, may continue to be taken until the end time on the next day. For example, snapshots that are scheduled to run every 1 hour beginning at 8:00 a.m. and ending at 7:00 a.m. on Thursday, may result in snapshots being created until Friday at 7:00 a.m.
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When backing up data from a single Business Server to multiple backup destinations, the snapshot schedules should be consistent so that all files that are protected by CPS are included in the snapshots.
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When scheduling snapshots, the minutes and seconds that are specified for the start and end times must be identical.
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