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Netapp snapshots & VMWare snapshots

We use Netapp snapshots/snapvault as a way to take backups of VMs.

This is done using a script that does something like this:

1. look for all VMs on a datastore

2. take a VMWare snapshot of all VMs on that datastore to quiesce the .vmdk file

3. take a netapp snapshot of the datastore

4. delete all VMWare snapshots taken in step 2.

All of this is done to ensure that the .vmdk file is not written while taking a Netapp snapshot.

Now, I'm wondering: as far as I know, the NetApp snapshot is an atomic action for an entire volume. So does it actually make a difference to quiesce the VMs beforehand, given that all .vmdk files of a VM are on the same volume ?

We've been successful in restoring non-quiesced .vmdks so I'm wondering if anybody has an opinion on this.

Re: Netapp snapshots & VMWare snapshots

Hi Karl,

I still believe that there are scenario's where you still can have a corrupt system: but my experiance is that the change is very low.

Now, in this case you are making a backup from your system-disk only? When you are running a database, you do the backup of your data on an other way?

When this is the case, than I think the risc is almost zero and when you take every hour a snapshot (NetApp level) without a vmware snapshot, than you will always have a copy that will boot (from the last 24 hours).

So my conclusion: for the system partition: no risc to do this. For your data, use an other way. We use snapdrive (with the microsoft initiator) in the VM for the backup of our data in our VMWare environment.

I have also a question: the delete of a VMWare snapshot works great with iSCSI (on ESX level) but our test with nfs is not so good. There we see a timeout of the VM for more the 15 seconds when the ESX is deleting a VMWare snapshot. Do you see the same?

Reinoud

Re: Netapp snapshots & VMWare snapshots

+++ <span class="jive-thread-reply-body-container">the delete of a VMWare

snapshot works great with iSCSI (on ESX level) but our test with nfs is

not so good. There we see a timeout of the VM for more the 15 seconds

when the ESX is deleting a VMWare snapshot. Do you see the same?+

Reinoud,

You need to change a setting on the ESX server, advanced settings, nfs, nfs.lockdisable = 1

But even then, occasionally ESX snapshots go haywire. That's why I'm considering to only use NetApp snapshots without quiescing the .vmdk files.

(important application data is never in the .vmdk files)

Re: Netapp snapshots & VMWare snapshots

Hi Karl, we'll try this asap.

But indeed, I have the same ideas about the use of VMWare snapshots.

Reinoud

Re: Netapp snapshots & VMWare snapshots

Hi,

we have made some backup on VMs on datatsores located on NFS.

Netapp has a tool called : VIBE (perl script) available for XP and Windows 2003 or Linux. It works fine.

You can:

- specify a specific or a list of datastores

- specific or a list of VMs or ALL

- request a crash-consistent snapshot on ESX --> VMWARE snapshot done before the snapshot of Netapp

- can also be include in your snapmirror scenarios --> Replication/DR

- can also be include in your Snapvault scenarios --> Backup to disk (Neartsore)

the only think that seems 'strange' is that when you have a crash-consistent snapshot include into your Netapp snapshot, when you will do the restore the VMWARE snapshot is back but the snapshot is not listed into ESX Snapshot Manager so you can't delete it from your VC. Maybe need to be done via script.

Regards,

Re: Netapp snapshots & VMWare snapshots

++<span class="jive-thread-reply-body-container">the only think that seems 'strange' is that when you have a+

crash-consistent snapshot include into your Netapp snapshot, when you

will do the restore the VMWARE snapshot is back but the snapshot is not

listed into ESX Snapshot Manager so you can't delete it from your VC.

Maybe need to be done via script.+

We did a recovery of a machine yesterday and had the same experience. Things are actually even worse, because trying to create additional snapshots on the recovered machine doesn't work any more, the poor thing is totally confused.

This strengthens my idea that it's actually better not to perform a VMWare snapshot before taking a Netapp snapshot. Recovering machines that have associated snapshots seems trouble.

Anybody has the same experience ? Comments ?

Re: Netapp snapshots & VMWare snapshots

Hi,

about the vmware snapshot restored I think I find a "solution" ...

You can't delete it from the VC .. because not listed into the Snapshot Manager in VM

so:

- create a fake snapshot snapshot on VM level --> can be done on VC or console

- all 'old' snapshot (also snapshot create during VIBE + fake ) are listed

- then you can delete all (unecessary) snapshots

Regards,

Eric

Re: Netapp snapshots & VMWare snapshots

If you're using VIBE with VMware snapshots, you should just those exclusively. Taking VMware snapshots with VIBE as well as VMware snapshots for other purposes can lead to VMware not knowing which snapshot to revert to. Ideally if you need the snapshot of a particular VM after the VIBE backup then simply connect to the datastore and get it from the VM directly.

It is an interesting use case question, though -- why might you need VMware snapshots with VIBE and other tools?

Thanks,

--Matt

Re: Netapp snapshots & VMWare snapshots

Lack of NFS file locking can cause two hosts to run the same virtual machine at the same time. This is bad and the VM will usually be corrupted very qucikly. This is no longer reccomended by Netapp or vmware. Performance issues around this and snapshot problems appear to be addressed in the latest set of patches

Re: Netapp snapshots & VMWare snapshots

just wondering..

can you give me the best way to implement VMware on Netapp ? What would be the best practice for VMWare on NetApp using NFS? Best practices for backing up VMware, etc..

this would help me in our Virtualization..

also, if you have some best practices also with Citrix/Xen virtualization coz we use both VMWare and Citrix for our Virtualization since we are RnD group.

Regards,

tons