- SnapCenter Server
- SnapCenter Plug-in for Exchange
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:
- 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,
1 snapshot(log) on active log volume per passive server
- 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,
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".
There are two kind of log backups. One is created with the full backup workflow. They typically have a backup snapshot with full backup name with an "_1" appended. If the full backup name is "Db1FullPolicy_<timestamp>", the log backup name should be "Db1FullPolicy_<timestamp>_1". One log backup is created by log backup policy. It is the name created just like a full backup name. The UTM for up to full backup setting decides what to retain.
For log backup retention (Up to the minute - UTM) in full backup workflow log backup deletion is global per database.
Considering the same example as above:
for DB1 policy1 with log UTM 3 count and policy2 with log UTM 2 count.
When full backup runs for policy 1, the UTM count 3 is applied. So all the log backups for this DB1 older than the 3rd newest full backup for policy 1 are considered for deletion.
When policy2 runs during full backup, UTM count 2 is applied and we are looking at all the log backups for DB1. So all log backups for this DB1 older than the 2nd newest full backup for policy2 are considered for deletion.
Caveat to remember:
During restore, when the full backup (snapshot) is retained and the user wants to do a UTM restore, the log backup snapshot ("..
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.