I'm hoping this is a known issue, or at least that someone here might have some experience with it.
To the very least, I'd love to know which logs to check.
Currently installed software:
Xen 4.1 4.1.2-2ubuntu2 (earlier version. A bug was back-ported in recently. Google: 22 invalid argument)
ZFS via ppa:zfs-native/stable (zfsonlinux.org kernel module, stable version)
Windows 7 DomU (HVM, PCI Passthrough for video card and USB card)
Herein lies the problem:
Originally I thought the ZFS module was still "unstable". It wouldn't finish a scrub (At around the 2.5tb mark on a 17tb pool) and would become unresponsive after heavy I/O operations. A cursory check of the logs found odd errors for the mvsas module.
Initially I thought that maybe I was burning through RAM by not limiting ARC on ZFS, and /proc/meminfo confirmed that suspciousion by showing me ~200 megs free (out of 24 gigs). So I capped the ARC at 4 gigs. My windows VM uses 11, I've got 24 on the host hardware, so I figured I was fine. And to an extent I was: MemFree stayed healthy. But ZFS, or at least the hardware underneath, was still experiencing issues, and I would occassionally get an unresonsive pool or VERY slow transfers (~1mbyte/sec, vs the ~250 it normally gets).
Then one day I rebooted it and forgot to start my Windows HVM guest up. Scrub completed without a single issue. System never once got slow, or unresponsive. Performance is great.
So the question is, wherein lies the cause here? Are there any known issues with PCI passthrough in earlier versions of Xen? The problem I listed above (22 invalid argument) has only very recently been diagnosed and fixed in Xen development (within the last three weeks). Could moving to a Dom0 mean I should recompile some modules with different options to better integrate with Xen? Is there any program that will issue a cursory sweep of installed modules and recompile for those circumstances?
I will gladly upload any logs, lspci info, whatever might help.
Any information would be greatly appreciated. I'd hate to have to wait 'til 14.04 (as I'm not sure that issue above is getting fixed in the current repo).
Edit Note: Possibly unrelated (but who knows): The Windows machine itself is stable for the most part, but there is one major flaw: After a while, HDMI audio through the video card being passed through fails dramatically. Sound starts to warble and slow down, and any app playing sound (xmbc, vlc, etc.) becomes very unresponsive and slow.