Anyone using Pernixdata and VB7?

[beckhamk]

I wanted to know if anyone is using or trialing Pernixdata and VB7 currently? If so, I wanted to inquire how you are handling your backups when a vm is in write back mode? We have been told that we have to use a backup proxy vm using VADP - which will allow the vm being backed up to flush its pending writes out to the san. But we are already using physical servers with direct san access and dont plan on switching. The only other option is to run a pre/post job script to flush the writes out.

[dellock6]

Oh, nice timing! I'm deploying Pernix in a couple of weeks in a production environment, and customer is using Veeam 7 right now. One of my concerns, or maybe one of the things I want to find out, is how the two interacts.
Basically, if you are using DirectSAN, you are not seeing the server-side caching solution, but reading directly from storage. So write-back caching is indeed a concern. My customer is using a virtual proxy, but I would be careful even in this situation, since Pernix is accelerating the VM, not the single VMDK, and I'm not sure how it behave when using hotAdd. Time I think to engage a couple of friends I have at Pernix and find it out

Luca.

[beckhamk]

Let me know what you find out. I would have thought that when VB takes a snapshot that they would pickup on that and flush the writes out. Then the mail disks should be ok while all new io goes to the snapshot. This has been the only show stopper we have seen. If we can atleast get the pre task configured it wouldnt be that bad.

[dellock6]

*IF* they see the snapshot and flush the cache, then it's ok with any backup method you choose, since the first step of every Veeam backup is taking a VM snapshot.
I just wrote the mail, let's see what they are going to reply, maybe it could end up in a sort of official statement to be used for the future. Server-side caching is starting to grow in polularity, so it's better to know how to handle it.
I'll update this post as I have something for you.

Luca.

[vnephologist]

Hi guys - hopefully you've both seen our (Andy Daniel from PernixData here) TR1007 document regarding backups using VADP products like Veeam. Email me (andy@) if not. The hot-add "proxy VM" method works well (we use Veeam in some of our labs, in fact), but beckhamk, you're right, it becomes more complicated when using a direct SAN connection. An "automatic" Write Through transition at the point of VMware snapshot unfortunately isn't an option because we have no way to instruct Veeam to wait for any de-stage to complete before making the direct SAN connection for backup. In this situation, the only option is to use a pre-script to transition any Write Back enabled VMs to Write Through mode before the snapshot is taken. To my knowledge, the most elegant way to do this would be to use Powershell to make the Write Through transition and then call the Veeam backup job.

[dellock6]

Hi Andy,
thanks for jumping into the thread to help.
As I wrote, I will have my first Pernix deployment in a couple of weeks, but this customer is using HotAdd, so the "blacklist" solution suggested in the document is ok. For the DirectSAN backup, I will have to test it in my lab, it's cool both Pernix and Veeam have complete Powershell cmdlets, so it would not be that hard to create a joint script to invoke both.

Luca.

[beckhamk]

Thanks guys! I am going to test out job chaining with the powershell script to see if I can get this working. Ideally we would like to see veeam add the ability for pre-job tasks - just like they have done for post-job tasks. that would help out a lot.

[vnephologist]

beckhamk, feel free to email me (andy@) for FVP Powershell pointers. I'll be glad to help.