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Backup Exec 2010/2012 Synthetic Backups

Created: 12 Apr 2013 • Updated: 12 Apr 2013 | 5 comments
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We are currently in the process of reviewing BackupExec2012 as we are running BE 2010 R3 my question doesnt really revolve around the version its more to do with synthetic backups. Our synthetics are run via a D2D backup policy

I understand that you run a baseline backup, then run incrementals that refernce the baseline, at the end of the week we run a full synthetic backup, my question is what the full synthetic does. Below is an example of what i am trying to understand

Disk 1 - Baseline backups

Disk 2 - Daily Incrementals that reference the baseline

Disk 3 - Synthetic Full backups

If there is a synthetic full backup run does it duplicate the baseline data or does it reference it and only put the data that is new from the incrementals and that synthetic full onto disk 3 or does it create a new full backup that replaces the baseline?

Any help would be greatful

Thank You


Operating Systems:

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Colin Weaver's picture

To explain the sequence would be something like

1) Full

2) Incremental 1

3) Synthetic (which combines full with Incremental 1 to make something that operates as Full)

4) Incremental 2

5) Synthetic (which combines incremental 2 with previous synthetic)

6) Repeat steps 4 and 5

You can of course have multiple incrementals between synthetics not just one.

And I would possibly recommend that maybe once a quarter, that a new baseline (from step 1) is run just in case something happens in the sequence that is not identifiable until you try to restore (this a rare possibility so it is just a precaution)

pkh's picture

When you do a synthetic backup, it is like doing a full backup at the time of the last incremental backup.  Once you have done an incremental backup, you will have a new baseline.  You either keep or delete the older baseline, depending on your retention requirement.

AgeasServer's picture


Thank you for swift response, i am curious though, is the size of the synthetic in step 3, is that going to be the size of a full backup or is it going to be a couple of new .bkf files that work with the baseline.

I only ask because if it just creates a new full backup that takes up all the room of what a full backup would whats the point of a baseline?

Thank You

pkh's picture

You cannot do any incremental/differential backups without a baseline.  As I said previously, a synthetic backup is a new baseline.  You can delete the old baseline if you don't want it.  The difference between doing a synthetic backup and doing a full backup is that with synthetic backups you do not have to go to your server and thus not interrupting/interfering with the server.

AgeasServer's picture


That does make sense then, we were thinking that be one of the reasons for it.

Thank You for your assistance