Installation onto existing SAN storage

[Merlin Hartley]

Greetings folks, I've been looking at FreeNAS for a few years now and played around with an installation or two - though never created a live product. I actually came across the product while looking for a free ZFS solution...

I am just about to replace our ageing Windows 2003 file server and I have come to the realisation that FreeNAS has the feature-set that I need (e.g. SMB, NFS, TimeMachine, AD integration)

Let me give a quick breakdown of our setup: we have a HP Blade system attached to Brocade SAN with HP P-2000 storage arrays. This provides an amazing amount of stability and flexibility for us and we run around 20 servers (on 8 physical blades) - all running natively on CentOS with Windows & CentOS Virtual Machines using KVM. We use LVM for disk management (on the host machines) and offer these as raw disks using VirtIO to the guest VMs - we rely on the P-2000 RAID6 for resilience (multipathd with 4 paths).

I was about to embark on installing FreeNAS into a VM on CentOS (KVM) with raw disks offered through the LVM of the host OS (via the SAN)....
...
Then I read horror stories on this forum of trying to use FreeNAS in a VM (with KVM especially mentioned as "you are on your own").
...
But it seems I may be OK as long as I use UFS instead of ZFS.

Am I really the only person that wants to run FreeNAS in such a way?
Will I lose any of the networked functionality (e.g. permissions/xattrs) if I use UFS instead of ZFS?
Should I really be looking for a different product? (perhaps Windows 2012R2?)

Many thanks for your time!

 

[jgreco]

Please go read the virtualization sticky.

There's a whole bunch of stuff to consider. Basically this is not a UFS-vs-ZFS thing, but rather a matter of scope, scale, purpose, and intent.

We *assume* you want your data to be secure and retrievable. FreeNAS has been designed with that in mind.

Most often what we end up seeing is some guy trying to cram ESXi onto an HP MicroServer N36L with 8GB total RAM, shaving off 4GB for FreeNAS, passing the disks thru to FreeNAS with RDM, etc. There are all kinds of fail built into that.

We know next to nothing about FreeNAS on KVM because - speaking as the "virtualization" guy here - nobody we know has gone that route successfully. ESXi can be bludgeoned into working, done that, know the ins and outs of it.

You start to lose things as you virtualize. For example, if you rely on a datastore on a RAID array, ZFS cannot access the redundant data on the RAID's parity disks if an error is detected. Therefore errors cannot be repaired, only reported. If you're passing disks through, then at least that isn't a problem.

If you are willing to spend time testing failure modes, you may be able to determine a golden path to virtualization on your platform. That's what I did for ESXi and that's what is described in the virtualization sticky. But basically we've seen many people come in here, cut corners out of either ignorance or desperation, and then have really really bad experiences. And without other people that have done the same thing as what you propose, when something goes bad, it can be really frustrating to know the answer to ... "what the heck do I do now?!?"

However, you are certainly welcome to try. Since you don't sound desperate to cut every corner, you have a better than average chance to get somewhere. Consider the paranoia that is built into the design outlined in the virtualization sticky. It is good, healthy stuff.