How many snapshots does SnapCenter create during the Exchange Backup?
Applies to
- SnapCenter Server (SC)
- SnapCenter Plug-in for Exchange (SCE)
Answer
How many snapshots does SnapCenter create during the Exchange Backup?
- SnapCenter creates a different number of snapshots during a backup based on the backup policy.
- At this moment (as per product design), SnapCenter creates the following number of snapshots per policy:
- Policy Full / Full+Log backup with active copy option:
- 1 snapshot(vss) on active db volume,
- 2 snapshot(vss+log) on active log volume,
- Policy Full / Full+Log backup with backup on servers option:
- 1 snapshot(vss) on passive db volume.
- 2 snapshot(vss+log) on passive log volume
- Policy Log backup with active copy option:
- 1 snapshot(log) on active log volume,
- Policy Log backup backup on servers option:
- 1 snapshot(log) on passive log volume.
- Policy Full / Full+Log backup with active copy option:
- If the DBs and logs are stored on the same volume (not best practice):
- Policy Full / Full+Log backup with active copy option:
- 2 snapshots (vss+log) on active DB volume
- Policy Full / Full+Log backup with active copy option:
What is the meaning/purpose of the snapshots with the "_1" at the end of the name?
- The log snapshot are the ones with the name ending with "_1"
- The log snapshot can be created by either a full backup or log backup policy
- Up-to-the-minute (UTM) retention is kept on a global per database level
- If backup policy #1 runs with UTM retention of 3 backups then backups older than the 3 most recent will be deleted
- If backup policy #2 runs on the same database, with UTM retention of 2 backups then backups older than the 2 most recent will be deleted
Additional Information
-
Remember: During restore, when the full backup (snapshot) is retained and the user wants to do a UTM restore, the log backup snapshot ("..
_1" ) taken by the full backup workflow is required. So when UTM count is smaller than full retention count and during retention for log backups, we only delete the log backup created by log backup policy and leave the log backup taken in the full backup workflow alone. So for the previous point, when Policy 2 has full backup retention 3 and UTM 2, what we actually delete is all the log backups older than the 2nd newest full backup, but keep the_1 snapshots alone if their full backup snapshot is retained. - As of SnapCenter 4.4 - UTM Retention must be equal to Full Backup retention so there is no gap created in the log backup chain. See BURT 1194218 for additional details.