THE WORD FROM GOSTEV ON ODX

[jorgene]

Hi,

I just read through this weeks Veeam Community Forums Digest.

If you are using Hyper-V 2012 and CSV, the following is an important hotfix to install > 2813630. Apparently, the lack of it have caused some damage during B&R POC with one large prospect of ours last week, and this was not pretty. Generally speaking, we have been seeing plenty of issues inflicted by ODX logic addition in our support, and our engineers commonly recommend to disable this functionality when storage behind CSV does not support ODX. So, consider disabling ODX preemptively to be on a safe side. The added benefit here is that this also removes overhead by eliminating unnecessary ODX support queries against the storage device during certain I/O operations.

I use Hyper-V 2012 and CSV, and a HP Lefthand P4300 ISCSI SAN and Veeam 6.5.0.128 and that works, so i'm in "no touch" mode until the issues are resolved in V7. I've seen people posting issues on W2012 and CSV's with paused VM's, insufficient disk space etc. But do you recommend that i disable ODX anyway in my current configuration?

[Gostev]

Veeam v6 did not support ODX at all, so installing our Hyper-V integration components would disable ODX. This is why you did not have any issues today, even without having the above referenced fix from Microsoft installed.

Veeam v7 does support ODX, so I recommend that v7 users install the above Hyper-V 2012 fix from Microsoft, or upgrade to Hyper-V 2012 R2 that includes this fix, or just disable ODX. Otherwise, you are taking chances - it can work fine for weeks, and then one day some unexpected high I/O activity may cause you to run into issues during backup.

[jorgene]

Ah.. ok thx for the answer. Just a question is ODX involved in my scenario (when Hardware VSS Provider, in case Lefthand) is resposible for creating the snapshot or is this only when Microsoft Shadow Copy VSS are used? (in the Backup process) or is it in the "copy/transfer" option itself?

Seems like i should install the patch and disable ODX before i upgrade to V7 if i understand you correctly.

[Gostev]

ODX has nothing to deal with snapshots or VSS. Instead, it makes copy and move operations where source and target is the same storage happen within the said storage, instead of going through the server that is performing the operation.

You should install the patch OR disable ODX, not both.