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pesos
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backing up a replicated VM - can't use CBT

Post by pesos » Sep 20, 2018 8:20 am

Hi all,

For some time now we've been doing Veeam replication of file servers from one colo to another (prod to DR). For the most part this has been an improvement over Hyper-V replica.

We have two independent veeam servers coordinating jobs on the hosts in their respective colos. The prod veeam does prod backup jobs locally as well as replication jobs over to the DR host. We then have independent backup jobs running on the DR veeam backing up the DR host.

The issue is that because veeam replicas require at least 1 snapshot ( annoying design flaw that I have asked about in the past but never gotten a straight answer about) that means there are always avhdx files involved. Because of the snapshot/avhdx limitation, CBT cannot be used and these jobs take 10-12x longer than their production counterparts.

I am looking for possible ways to avoid this - but ideally still be able to take independent backups - however it appears this may not be possible. So second best would I guess be to forget about independently backing up the replicas and instead ship the prod backups to the DR colo. I used resilio sync to sync the prod backup to the dr colo and imported the synced repository into the DR veeam server - but I do not see a way to build a replica from the imported backups (in fact they do not really appear to be showing up properly in the DR veeam instance anyway).

Any suggestions are welcome on ways to improve the approach - thank you!

Vitaliy S.
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Re: backing up a replicated VM - can't use CBT

Post by Vitaliy S. » Sep 20, 2018 4:07 pm

Hi John,

If I were you I would use built-in backup copy jobs to ship your prod backups to the offsite location. This would allow you to avoid putting additional stress on production VMs twice to take backups. As for the hot spare VM replicas, then running these from the server installed in the offsite (DR) location makes total sense, as you will have an ability to immediately fail over VMs via Veeam backup console after the main site goes down.

Thanks!

pesos
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Re: backing up a replicated VM - can't use CBT

Post by pesos » Sep 20, 2018 4:37 pm

Thanks Vitaliy. Currently we have the replication jobs running every hour so that the replica is not too far behind production. We only do backups each night. So if we were to use copy jobs and run DR from those copies, we'd always be 24-48 hours behind the production state, wouldn't we?

Vitaliy S.
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Re: backing up a replicated VM - can't use CBT

Post by Vitaliy S. » Sep 20, 2018 7:30 pm

Yes, you would, but as far as I understand you have 1 backup, 1 backup copy and VM replicas and you would like to maintain that, right? What I proposed was using backup copy jobs instead of "resilio", while keeping your replication jobs as is (using production VMs as a source).
pesos wrote:but I do not see a way to build a replica from the imported backups (in fact they do not really appear to be showing up properly in the DR veeam instance anyway).
If you follow the approach above, there will be no issue with CBT for the backup jobs using VM replicas as a source. Hope this clarifies my answer!

pesos
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Re: backing up a replicated VM - can't use CBT

Post by pesos » Sep 20, 2018 8:01 pm

The current configuration is:
1) production servers are backed up in production colo
2) production servers are replicated directly to DR colo once an hour
3) replica servers are backed up independently in DR colo (no CBT possible due to snapshot)

I'm not clear how you are saying we can back up the replicas (which have at least one snapshot) with CBT. We would like to have zero snapshots, but Veeam replication does not allow this.

Mike Resseler
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Re: backing up a replicated VM - can't use CBT

Post by Mike Resseler » Sep 21, 2018 5:21 am

What Vitaliy says is to do it a bit different (step 3)
That would become:
Step 3: Use the backups from step 1 to do a backup copy job and sent those to the DR colo.


Makes sense?

pesos
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Re: backing up a replicated VM - can't use CBT

Post by pesos » Sep 21, 2018 5:26 am

Thanks Mike - yep I get that as a possibility. Only issue is that we then lose having two separate independent backups (if something is corrupted in the primary backup, we don't have a secondary backup to fall back on)…

Is there any reason that Veeam replication doesn't allow a "zero snapshot" option - i.e. no avhdx so CBT could be used for replicas like with hyper-v replica?

thanks!

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Re: backing up a replicated VM - can't use CBT

Post by Mike Resseler » Sep 21, 2018 5:34 am

Veeam uses snapshots to do the replication, it can be compared with incremental backup actually. We have a full and a chain of snapshots (the AVHDX-es). That is the reason why we can't take a backup of it. I understand your concern (for the corruption) but I would like to counterargument that ;-)


A backup copy job is especially built to make sure you are not suffering from corruption. You can have different schedule, different merge times and so on for the backup copy job. This is to make sure that when you lose the primary backup (because of corruption for example) you still have the copy to fall back on. (The famous 3-2-1 rule ;-))

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Re: backing up a replicated VM - can't use CBT

Post by Mike Resseler » Sep 21, 2018 5:36 am

By the way, forgot to mention that Hyper-V replica uses journaling replication which is different from our snapshot technology. But they can use an internal system to achieve this which we can't since we cannot connect to these API's

pesos
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Re: backing up a replicated VM - can't use CBT

Post by pesos » Sep 21, 2018 5:39 am

Thanks Mike. I get that snapshots are used to do the replication, but I guess my question is why not have the option for zero retention points (like Hyper-V replica)? Currently we do 1 snapshot (the minimum) because we can't do zero - why couldn't the product have a zero option that would simply merge that replicated data (snapshot) into the replica at the end of the replication job so that we end up with a replica consisting of snapshotless vhdx files that could then be backed up with CBT?

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Re: backing up a replicated VM - can't use CBT

Post by Mike Resseler » Sep 21, 2018 5:53 am

As said, the mechanism is different between us and Hyper-V replica. One uses journaling and we are using snapshots. I can take this request to the DEVs and ask them about their opinion but knowing how the internal system works I'm afraid that won't be such an easy tasks

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Re: backing up a replicated VM - can't use CBT

Post by Vitaliy S. » Sep 21, 2018 11:18 am

pesos wrote:Is there any reason that Veeam replication doesn't allow a "zero snapshot" option - i.e. no avhdx so CBT could be used for replicas like with hyper-v replica?
Yes, similar to vSphere replication jobs we create one snapshot to accommodate all changes from the production VM. This is essential, as imagine your replication job fails in the middle of the task, if we didn't create that snapshot, your target VM would be also corrupted (useless). Hope this clarifies this!

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Re: backing up a replicated VM - can't use CBT

Post by nmdange » Sep 21, 2018 2:09 pm

Mike Resseler wrote:
Sep 21, 2018 5:36 am
By the way, forgot to mention that Hyper-V replica uses journaling replication which is different from our snapshot technology. But they can use an internal system to achieve this which we can't since we cannot connect to these API's
If Veeam could create and orchestrate native Hyper-V Replicas as an alternative to using snapshots for replication, this would be a nice feature to have. Since Hyper-V replica can be managed through PowerShell, this should be possible.

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Re: backing up a replicated VM - can't use CBT

Post by Mike Resseler » Sep 25, 2018 10:23 am

NMdange,

You just want to see Hyper-V replica's in our UI? And the possibility to manage those? Is that correct?

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Re: backing up a replicated VM - can't use CBT

Post by nmdange » Sep 25, 2018 2:59 pm

Mike Resseler wrote:
Sep 25, 2018 10:23 am
NMdange,

You just want to see Hyper-V replica's in our UI? And the possibility to manage those? Is that correct?
Correct, even if I have to create them manually within Hyper-V, being able to orchestrate the failover of native Hyper-V replicas using Veeam would be a welcome addition. e.g. being able to include failing over a native Hyper-V replica within a Veeam failover plan.

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