VeeamB&R and CSV

Hyper-V specific discussions

VeeamB&R and CSV

Veeam Logoby baltechnique » Mon Jun 16, 2014 2:00 pm

Hi,

why is Veeam doing a volume snapshot for each VM, even if these VMs are on a Cluster Shared Volume.

An only snapshot for each CSV would be far enough. No ? And backup would finish faster.

PS : tested on 2008R2 HyperV Cluster, but not on 2012R2
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Re: VeeamB&R and CSV

Veeam Logoby Gostev » Mon Jun 16, 2014 6:01 pm

Hi

Reliability reasons. This approach does not currently work reliably (issues on Hyper-V VSS side). Too many intermittent VSS failures.

We actually have this logic implemented, and may end up enabling it in v8, but it will still be heavily limited to no more than a few VMs per CSV being processed at once. Folks with really fast SAN will be able to tweak the maximum amount, but for average hardware, the limit will need to be pretty low (think 3-4 VMs at once).

Thanks!
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Re: VeeamB&R and CSV

Veeam Logoby baltechnique » Tue Jun 17, 2014 7:10 am

Hi,

OK for your explanation, but in facts i dont understand why :)

Since there is a SAN snapshot of the volume, each VM file is available separately (i'm not talking about vss inside the running VMs for application consistency), and since the snapshot is finished on the SAN, the redirected mode is back to normal mode for hyperV.

But i do agree that even with hardware VSS there are some snapshot failure, so in that case you failed to backup correctly each VM in this volume.
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Re: VeeamB&R and CSV

Veeam Logoby rskinner » Tue Jun 17, 2014 8:06 am

Gostev wrote:Hi

Reliability reasons. This approach does not currently work reliably (issues on Hyper-V VSS side). Too many intermittent VSS failures.

We actually have this logic implemented, and may end up enabling it in v8, but it will still be heavily limited to no more than a few VMs per CSV being processed at once. Folks with really fast SAN will be able to tweak the maximum amount, but for average hardware, the limit will need to be pretty low (think 3-4 VMs at once).

Thanks!


This would be a great feature. Many of our VMs have very few data changes and the time to create the CSV VSS snapshot (2-4 mins) is one of the longest stages in the backup process for each VM. The ability to have 3-4 VMs backed-up per CSV VSS snapshot would greatly speed up our backups.
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Re: VeeamB&R and CSV

Veeam Logoby Gostev » Tue Jun 17, 2014 9:48 am

baltechnique wrote:Since there is a SAN snapshot of the volume, each VM file is available separately (i'm not talking about vss inside the running VMs for application consistency), and since the snapshot is finished on the SAN, the redirected mode is back to normal mode for hyperV.

Yes, but unfortunately it does not work like that today :)

Hyper-V backup is an incredibly integrated monster that touches too many things. Part of the process actually goes into each guest, creates VSS snapshots inside of the running VMs, and then after SAN snapshot is created, it goes back there and performs the process known as AutoRecovery. So as soon as you have more than a few VMs in the consistency group, this process starts to fail or timeout due to much extra load on the datastore. Hyper-V team at Microsoft is well aware of this problem, in fact I've just discussed this issue again with them last month at TechEd. But the whole talk was under uber NDA, so I cannot really comment beyond known facts.
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[MERGED] Snapshot multiple VMs at once

Veeam Logoby samh22a » Thu Sep 11, 2014 2:47 am

Hi,

Let's assume the following scenario

- Hardware VSS Snapshot
- Hyper-V cluster
- CSV with 10 Virtual Machines

Is there any way to take a single snapshot, and backup the 10 VMs at once ? right now I can see multiple snapshots beeing created as it process all of those vm..and it doesn't seems to be very efficient

Thanks
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Re: VeeamB&R and CSV

Veeam Logoby rmeichsner » Tue Dec 02, 2014 2:29 pm

Hi Anton,

can you share any details under which circumstances this option should work in v8? The explanation in your kb is really general and doesn't contain much information regarding this option.
In our environment the setting doesn't seem to have any effect at all. (smb3 sofs)

What is the maximum number of Snapshots you recommend per smb3-Volume? If set to everything different than "1", we're facing VSS Errors from time to time...
Registrykey "HyperVRestrictConcurrentSnapshotCreation" already set to "1".

We're looking for a way to reduce the time, the backup procedure needs and get rid of the gaps in the backup process without any throughput.

Thanks,
Ruben
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Re: VeeamB&R and CSV

Veeam Logoby foggy » Tue Dec 02, 2014 4:28 pm

Ruben, there is a setting in the job advanced settings that allows processing of multiple VMs from a single snapshot. The setting is enabled by default on the new jobs, however you should enable it manually for existing jobs.

Also, here's the quote from the What's New document regarding this feature:
Consistency groups: Jobs can now process more than one VM from the volume snapshot at a time instead of creating a separate volume snapshot for each processed VM. For reliability reasons caused by Hyper-V backup architecture, the maximum amount of VMs is limited to four per snapshot by default in case of software VSS, and eight per snapshot in case of hardware VSS, but can be increased on fast primary storage with the MaxVmCountOnHvSoftSnapshot (DWORD) and MaxVmCountOnHvHardSnapshot (DWORD) registry values under HKLM\SOFTWARE\Veeam\Veeam Backup and Replication key.
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Re: VeeamB&R and CSV

Veeam Logoby rmeichsner » Tue Dec 02, 2014 5:16 pm

Thanks for your fast answer, but unfortunately it's not the solution.
The Settings you mentioned are already set, but doesn't seem to have any effect at all.

MaxVmCountOnHvHardSnapshot and MaxVmCountOnHvSoftSnapshot are both set to 8.

That's the reason, why I'm interested in the requirements which have to be met to have this option taking any effect.
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Re: VeeamB&R and CSV

Veeam Logoby foggy » Tue Dec 02, 2014 9:36 pm

The main requirement is that only VMs residing on the same host can be processed from a single snapshot.
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Re: VeeamB&R and CSV

Veeam Logoby baltechnique » Tue Dec 16, 2014 8:46 am

foggy wrote:The main requirement is that only VMs residing on the same host can be processed from a single snapshot.


Hi,

Is it needed by the Backup Job to have these VMs declared together ?

For instance if VM1 and VM3 are stored on the same CSV must i modify it like this :
VM List : VM1, VM3, VM2, VM4
or VM1, VM2, VM3, VM4 does also work ?

and you're also saying that i must migrate all VMs sharing same CSV (at least 4 by 4 or 8 by 8 if using hardware VSS) to same HyperV Host before backup ?
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Re: VeeamB&R and CSV

Veeam Logoby v.Eremin » Tue Dec 16, 2014 9:22 am

For instance if VM1 and VM3 are stored on the same CSV must i modify it like this :
VM List : VM1, VM3, VM2, VM4
or VM1, VM2, VM3, VM4 does also work ?

It should work either way.

and you're also saying that i must migrate all VMs sharing same CSV (at least 4 by 4 or 8 by 8 if using hardware VSS) to same HyperV Host before backup ?

If you want those VMs to be processed from a single volume snapshot, then, yes.

Thanks.
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[MERGED] Allow processing of multiple VMs with Single-Volume

Veeam Logoby jmeisel » Tue Mar 10, 2015 1:53 pm

We are running Veeam Backup & Replication 8 Patch 1 with an FC-attached off-host Proxy. Everything running on Windows Server 2012 R2.
Our Storage, where the cluster-shared-volume for the HyperV-VMs is on, is a NetApp.

In our testing-environment we are having a strange issue with the "Allow processing of multiple VMs with Single-Volume-Snapshot" Option. It seems as if this Option is useless. It doesn't matter if the Checkbox is checked or unchecked. The Backup-Job that should backup several VMs that are running on different HyperV-Hosts where all the VM data is stored on the same CSV (=ONE Volume) is always trying to create a Hardware VSS-Snapshot for each VM. And... because the disk / volume signature would be the same, the snapshot creation is failing for each VM, except for one.

Can anybody confirm this???

We have NetApp Snapdrive installed on every server. We are utilizing the Hardware VSS-Provider from NetApp. We adjusted the Volume-Shadow-Reserve on every HyperV-Host to 10GB (for the CSV).
At the moment we are wondering what's going on here...

Any ideas?
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Re: [MERGED] Allow processing of multiple VMs with Single-Vo

Veeam Logoby foggy » Tue Mar 10, 2015 3:35 pm

jmeisel wrote:The Backup-Job that should backup several VMs that are running on different HyperV-Hosts...

That is the reason, for VMs to be processed from a single snapshot, they should reside on the same host.
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[MERGED] : Optimal job design

Veeam Logoby frankive » Fri Apr 24, 2015 1:06 pm

For a small hosting company, running 2 node hyper-v failover cluster with different customeres and multiple CSV (Sans);
what is the most efficient way to backup regarding speed?
A job where each customers VM is no matter what which CSV they belong too?
Or a larger job with all the VMS where any customer is on the same CSV?

I believe that one job (with max 20 VM) backing up VMS which belongs on the same CSV) is optimal?
No VMS are having separate vm-disks on the CSVs.

and if we enable the job to use one shapshot for multiple vms, will 20 VM use that one shapshot? That seems to be very efficient?
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