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Simultaneous backup of VMs in a single CSV from multiple nodes

kokey
Not applicable

Hi,

 

I am wondering if any of you guys have tested backing up multiple VMs from one Clustered Shared Volume in Hyper-V 2008 R2? According to the NBU for Hyper-V guide:

  • During the backup, the cluster-shared volume (CSV) enters the online state (“Backup in progress, Redirected access"). The cluster node that performs the backup becomes the owner of the CSV.
  • Multiple nodes cannot back up a CSV simultaneously. When a node backs up a virtual machine on a CSV, the attempt by another node to back up the same virtual machine fails.
  • You can use the CSV Timeout in Minutes option in the policy to adjust how long NetBackup waits for another backup of the same CSV to complete.
  • A single node containing two virtual machines can back up both machines simultaneously, even if they use the same CSV. As long as both virtual machines reside on the same node, simultaneous backups are allowed.

I have multiple nodes in a cluster and they host different VMs obviously. If i try to backup all the VMs from the cluster and it only has one CSV, will only one node be able to backup its VMs simultaneously and the other nodes wait until this node releases the CSV?

11 REPLIES 11

RiaanBadenhorst
Moderator
Moderator
Partner    VIP    Accredited Certified

Correct.

 

If you log a case with Symantec they will suggest that you create a CSV per VM (or at least more CSVs). Had the same issue with a client ourselves.

 

The problem is, as you noted, with the CSV, multiple hosts cannot access it for backup purposes at the same time. This becomes an issue when your VMs are spread across hosts. Its a MS CSV limitation and forces you to perform the backups of the VMs contained on a CSV serially (one-after-another).

Omar-Torres
Level 2

Hello, I think I'm having the same issue but I'm not sure I understand how this works. I have two nodes using one CSV for all my VMs. All the VMs are HA so I select them through the cluster itself and not from the hosts since they don't show up there.

Right now my backup job backs up all the VMs on one host and fails for the ones running on the second host. Are you saying that in order for me to backup all my VMs I need one job for the VMs in one node and then a separate job for the ones in the second node? The other solution of one CSV per VM is almost like not using CSVs.

AsiyeYigitGante
Level 2
Partner Accredited Certified

Hello All;

as Omar-Torres said that one CSV per VM is not acceptable many time in the customer environment.

it means not use CSV at all.

 

we are using netapp Hw provider to backup hyper-v. however, netapp says that just one snapshot per LUN. so, if the environment is huge, there is no way to saty in backup window for all VM.

another important point, although we use cluster name to backup VM hosts, if the vm is migrated to another node, the backup fails. however, in the guide, it seems it is okay to backup VMs via cluster name regardless of migration or not to another node before backup. it doesn't work in practice life.

it fails.

 

so, i am searching the best practice if we have many VMs per Luns and we are using netapp HW provider.

 

best regards

Omar-Torres
Level 2

Asiye, this is how I fixed the issue. I disabled AOFO. The Advanced Open File Agent takes a snapshot of the entire CSV and starts backing up the VMs. The problem is that it can backup the vms that are running on SERVER1 but when it tries to backup the ones on SERVER2, it can't access those files as they are "held" by the snapshot created on the first server. This is what I saw happening.

I found a document somewhere on Symantec's site that said they did not recommend using AOFO for Hyper-V VMs so I disabled AOFO and voila! It's been working perfect ever since.

I wish they would put stuff like that somewhere accessible. There should be documentation about best practices on how to backup Hyper-V, Exchange servers, SQL and so on and so forth. Sadly you have to have issues to go to the knowledgebase or contact Symantec support to find out about these things.

Let me know if this fixes it for you!

Lynne_Seamans
Level 6

I believe we are having the same problem, and I've spent all morning searching and still can't find out HOW to diable AOFO for Hyper-V backups.. 

It's probably me, but can someone please point me in the right direction?

Omar-Torres
Level 2

You can't disable only for Hyper-V backups unfortunately, only at the job level. So you'll have to create a Hyper-V only backup job and disable AOFO there. I included a screenshot in case you need it.

Lynne_Seamans
Level 6

Maybe we're not talking about NetBackup?  I don't have a "Jobs" screen at all.. 

Omar-Torres
Level 2

Yeah you're right, I'm on Backup Exec. Let me see if I can find the document on AOFO for Hyper-V. I don't think it was BE-specific.

Lynne_Seamans
Level 6
Thanks so much!

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

In NetBackup the Open File Option is disabled in Host Properties -> Master Server -> Client Attributes -> Add/select Client, Windows Open File Backup tab.

Lynne_Seamans
Level 6

Thank you !  Now if they tell me to turn it off, I'll know where to go.