FreeNAS 8.3 on QEMU/KVM

[atomspring]

Hello everyone, I used to be a lurker on these forums but am being forced to post due to a bit of an issue I'm experiencing.

I manage a Linux-based KVM/Qemu virtualization system, the host hardware supports full virtualization, 12Gb ram, 12x 1.6ghz cores, etc.
The problem I'm experiencing is that the FreeNAS instance (amd64 FreeBSD 8.3-RELEASE-p5 #2 r244158M) has been assigned two cores and 2Gb ram, and is using close to 100% of one of the host processor (the other core hovers at around 13%).

FreeNAS is providing 1Tb of ZFS provisioned space via NFS, the load average is 0.41, 0.25, 0.28 and top shows that the only process going above 2% cpu is the NFS daemon.. which is at about 5%.

QEMU doesn't appear to support anything more than C1 for the CPU, and when I try starting powerd, I get "powerd: lookup freq: No such file or directory"... I've tried "kldload cpufreq", but I can't even find the cpufreq module, despite doing a "find" from the root of the install. Mind you, the last time I ran FreeBSD was around 8.2 several years back, so perhaps things got reorganized.

So.. does anyone have any ideas where to go from here? I'd like to reduce CPU usage on the host machine if possible. Or at least figure out why the CPU usage is so consistently high. I appreciate the help :)

 

[sirtech]

We're using FreeNAS-8.3.0-RELEASE-p1-x64 (r12825) on Qemu 0.13 and a custom 2.6.32 kernel with no bugs yet (performance tanks compared to Linux because of no Virtio drivers, but that's not really a 'bug'). Idle VM = idle host no issue. Maybe it's your version of Qemu / the kernel (and hence KVM code version).

 

[atomspring]

Looks like there was something going on in the background, the CPU usage for the VM has gone back down to a little less than 5% consistently.. Sweet.

Little worried because it seems like a Heisenbug, but whatever. Thanks for the advice sirtech.