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I'm speccing out sandbox VM servers for developers at my company. The requirements for the dom0 hosts are: local, deduplicated ZFS storage (no separate storage servers), and Xen 4.1+ (4.2 is ideal).

I checked out Oracle VM, but it only has Xen 4.0. I also looked at the Xen official list of supported dom0s, but none of the ZFS-supporting ones (openindiana/illumos and opensolaris) seem to be current enough to run Xen 4.1+.

Question:

What operating systems out there have robust (read: stable and decent performance) support for ZFS/dedup, and can smoothly (read: good hardware compatibility) work as dom0 hosts for Xen 4.1+?

If possible, I'd like to avoid compiling Xen and have a stable package, but if that's the way it has to be, I can deal with it. I'd similarly prefer ZFS support to be integrated, rather than run through one of the hack-on kernel extensions/FUSE modules available for non-Oracle Linuxes. Again, if that's not possible, I can deal.

If you care about the why: The devs need Xen 4.1 or better to do something weird I'm not clear on with CAD and passthrough, and management likes ZFS, so that's a "must have" as well. I know that dedup'd ZFS uses a load of hardware resources, but the powers that be are fine with dumping money into hardware.

Mark Henderson
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Zac B
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  • Any resolution? – ewwhite May 05 '12 at 13:33
  • Playing around with hacking the FUSE drivers, with a stability test planned in the near future, and messing with Nexenta. I'll give you the check, since you've definitely given me some great pointers. I'll put more info here when I have results. Juggling lots of projects, unfortunately... – Zac B May 07 '12 at 18:27

2 Answers2

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It sounds like a bad spec. These are disparate technologies... Something like SmartOS may be more fitting, except for the Xen requirement.

If you want ZFS, that's fine. But to do ZFS storage properly and support deduplication without a risk of performance problems, you will need to engineer for it. That means lots of RAM, possibly augmented with an approved L2ARC SSD cache device. Is this really a use-case for deduplication, or will compression be sufficient? If compression is good enough, then you have more options.

A separate storage device will be the most supportable and scalable solution. That way, you can avoid using immature (at this time) Linux ports and direct the resources into single-purpose hardware. It also gives you flexibility to use the virtualization technology of your choice impacting the entire environment or having to navigate strange dependencies.

I recommend NexentaStor as a ZFS storage solution, but you can certainly roll-your-own with OpenIndiana

What type of hardware will you be using? The ability to pass raw disks to ZFS is going to be crucial, too.

Community
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ewwhite
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  • I'm the first to admit it's a bad spec, but I'm stuck with it. Aren't office politics fun? Good ideas, though. I'll poke around. – Zac B Apr 20 '12 at 15:48
  • Also, on investigation it doesn't look like KVM as a hypervisor allows passthrough of graphics cards well, which are needed for CAD apparently. – Zac B Apr 20 '12 at 15:55
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    Well, don't let politics dictate a potentially tough solution. I'd split the technologies. Xen has been left by some vendors for KVM. So finding a supported ZFS solution that also accommodates Xen is going to be tricky... But building Xen hosts and having separate ZFS storage is easily attainable. – ewwhite Apr 20 '12 at 15:57
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ZFS and Linux? It seems to be possible - but far from stable - as this blog post indicates.

If you really need XEN 4.1 use SLES11 SP2. I am in the progress of migration from SLES10 SP4 to there. SP2 has XEN 4.1.2 built in. Further service packs will propably upgrade, too. SLES11 started with 4.0...

BRTFS might be a good FS for your purposes, too.

Nils
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