Restore incremental backup on top of which full backup ?

[marsVoyager]

Hi,

I am not at all familiar with VEEAM products but I have heard an explanation I'd like to check with you gurus.

We full back up our VM once a week, with incrementals backed up daily.

Like, we backed up :
Full1 then Inc1, Inc2, ..., Inc6 then
Full2 then Inc8, Inc9

When that VM crashed we needed to restore Inc9. Problem was, Full2 would not restore, so our latest restorable full back up was Full1.

Is it possible by any stretch of imagination, that the VM be restored past Inc6 ? I was told Inc9 could restore after Inc6 because nothing much was changed in the system in the last 3 or 4 days. I don't understand how that would work.

Thanks for you light

[veremin]

Sorry I didn't get your question, so, more detailed explanation would be appreciated.

If full 2 as well as increments dependent on it are corrupted, you will be able to restore only from previous unbroken restore points. In your case, full1, inc1, inc2, inc3, inc4, inc5, inc6.

Thanks.

[marsVoyager]

Thanks for picking this post,

Full2 only is corrupted (althought nothing in the backup log shows this). I am told that increments from Full2 (inc8 and inc9) can be used.

I don't understand how that would work. Not on the system I am used to anyway.

[veremin]

I am told that increments from Full2 (inc8 and inc9) can be used.

What is the source of this knowledge? I'm wondering since if the full backup corruption makes dependent increments useless. Thanks.

[marsVoyager]

full backup corruption makes dependent increments useless

I understand the increment is useless when it depends on a corrupt full backup.

I suppose Veeam knows that, and would'nt let an operator restore such an increment, right ? Like increment 8 would not be restored, in my first example ?
I mean Veeam surely can't let that happen because the system would probably be unstable ?
Or is there a way to force increment 8 to be restored (and then face the consequences...).

Pretty obvious stuff but we need to understand what was restored after a VM crash and our local explanation is somewhat short.

[VladV]

If I'm not mistaken I think there is a misunderstanding here.

Standard forward incremental is composed of a full backup and future incrementals until the next full backup is created.
In your case every Inc from Inc1 to Inc6 is dependent on Full1 and Inc8 and Inc9 are dependent on Full2. Data in those incrementals are only changed blocks from the previous backup. Thus you cannot restore mostly anything with a chain corruption.

If you want to restore a VM state from the day Inc9 was taken, you simply choose that restore point and restore. Veeam takes care of the data needed to restore from all increments and full.

What actual error din you receive when you tried to restore from one of the increments?

[marsVoyager]

I have never used VEEAM myself, and I don't have the technical details of what was exactly done nor the error message. I've only had a conversation with the person who was in charge with the recovery that day. I'll get down to the facts next oportunity I have.
Thanks for describing the process of restoring, it is simple enough.

[nicomaque.jette]

Hi, this is an old thread however the subject line is exactly what we are looking for; is there a way with Veeam to apply an incremental backup on top of an existing copy of the original full backup?

Our goal is to:
- make a full backup once a week (VM on server #1)
- make a full restore to a dormant VM (on server #2)
- make incremental backup daily (VM on server #1)
- in case server #1 is down, apply only the incrementals backup on top of server #2)

Full restore for us takes 3 hours, and we are looking to make it as short as possible.

Thanks for your feedbacks!

[foggy]

Hi Nicomaque, since the restored VM would have a different VM ID, it will be treated by Veeam B&R as a different VM, hence a full VM backup will be triggered anyway.

[nicomaque.jette]

Many thanks @foggy for the precisions