Host-based backup of Microsoft Hyper-V VMs.
Post Reply
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

Case # 02531465

We have a couple of older VMs (2003 R2 and SBS 2008) that always fail VSS Application Aware Processing.

Currently, we have them set to "try application processing, but ignore failures" - and the VMs complete with a warning that Guest processing was skipped.

We don't want to spend too much time troubleshooting the VSS issues, because the Servers will be decommissioned in the near future.

Is it better to set the VMs in that job to "try application processing, but ignore failures" or disable AAP and enable Hyper-V guest quiescence and take crash consistent backup?
Mike Resseler
Product Manager
Posts: 8044
Liked: 1263 times
Joined: Feb 08, 2013 3:08 pm
Full Name: Mike Resseler
Location: Belgium
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by Mike Resseler »

Hey BCT-Tech,

That will depend. What workloads are those VMs running. The SBS 2008 I'm a bit scared off because it most probably runs exchange and AD and a crash consistent backup might be not the best idea when you need to restore.
nmdange
Veteran
Posts: 527
Liked: 142 times
Joined: Aug 20, 2015 9:30 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by nmdange »

If you enable Hyper-V Native Guest Quiescence, then the Hyper-V integration services will initiate a VSS snapshot in the guest as long as "Backup (Volume Snapshot)" is enabled in the integration services, so it will still be application consistent. If the issue is with VSS in the guest, then it will most likely fail using native quiescence as well, but it's worth trying to see if there is a difference.
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

nmdange wrote:If you enable Hyper-V Native Guest Quiescence, then the Hyper-V integration services will initiate a VSS snapshot in the guest as long as "Backup (Volume Snapshot)" is enabled in the integration services, so it will still be application consistent. If the issue is with VSS in the guest, then it will most likely fail using native quiescence as well, but it's worth trying to see if there is a difference.
Are you talking about enabling Hyper-V Native Guest Quiescence, but not crash consistent backup?
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

Mike Resseler wrote:That will depend. What workloads are those VMs running. The SBS 2008 I'm a bit scared off because it most probably runs exchange and AD and a crash consistent backup might be not the best idea when you need to restore.
Exchange has been "disabled" on that Server, and it is their only Domain Controller for now.
nmdange
Veteran
Posts: 527
Liked: 142 times
Joined: Aug 20, 2015 9:30 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by nmdange »

BCT-Tech wrote: Are you talking about enabling Hyper-V Native Guest Quiescence, but not crash consistent backup?
The setting "Take crash consistent backup instead of suspending VMs" in Veeam is really only applicable to Windows Server 2012 R1 and earlier, which used to suspend VMs that could not do online backups. As long as you have "Backup (Volume Snapshot)" enabled in the properties of the VM in Hyper-V, it will do an in-guess VSS snapshot and if that fails, the backup will fail with a VSS error, it does not fall back to crash-consistent. To do that you have to disable that integration services setting on the VM in Hyper-V.
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

nmdange wrote:The setting "Take crash consistent backup instead of suspending VMs" in Veeam is really only applicable to Windows Server 2012 R1 and earlier, which used to suspend VMs that could not do online backups. As long as you have "Backup (Volume Snapshot)" enabled in the properties of the VM in Hyper-V, it will do an in-guess VSS snapshot and if that fails, the backup will fail with a VSS error, it does not fall back to crash-consistent. To do that you have to disable that integration services setting on the VM in Hyper-V.
Won't native quiescence pause the VM while it is being backed up?
nmdange
Veteran
Posts: 527
Liked: 142 times
Joined: Aug 20, 2015 9:30 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by nmdange »

No that behavior is only applicable to Windows Server 2012 R1 and earlier. 2012 R2 and later do not pause VMs during backup. https://blogs.msdn.microsoft.com/virtua ... s-anymore/
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

nmdange wrote:No that behavior is only applicable to Windows Server 2012 R1 and earlier. 2012 R2 and later do not pause VMs during backup. https://blogs.msdn.microsoft.com/virtua ... s-anymore/
Just to verify - you are talking about the Host correct? As long as the Hyper-V Host is 2012 R2 or newer the VMs will not pause?

Or are you talking about if a VM is 2012 R1 or older?
nmdange
Veteran
Posts: 527
Liked: 142 times
Joined: Aug 20, 2015 9:30 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by nmdange »

Yes sorry, as long as the Hyper-V host is 2012 R2 or newer. Guest OS does not matter.
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

OK, I will change the job to disable AAP and enable Hyper-V Native Guest Quiescence, but not crash consistent backup.
BCT-Tech
Service Provider
Posts: 78
Liked: 1 time
Joined: Mar 20, 2015 6:12 pm
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by BCT-Tech »

All VMs backed up successfully last night with these settings.
Nail.Mukhametshin
Enthusiast
Posts: 51
Liked: 3 times
Joined: May 05, 2016 1:15 pm
Full Name: Наиль Мухаметшин
Location: Russia, Moscow
Contact:

Re: Skip VSS or enable Crash Consistent?

Post by Nail.Mukhametshin »

BCT-Tech, check this feature request: microsoft-hyper-v-f25/feature-request-i ... 38197.html. May be this that you need. If so, please post there "+1" message. I think this can help to provide this feature request faster ;)
Nail Mukhametshin | System Engineer | R&D Services Infrastructure Development | Kaspersky Lab
Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests