kern/177536: zfs livelock (deadlock) with high write-to-disk load

[Kevin Day]

On Apr 4, 2013, at 11:07 AM, Andriy Gapon <avg at FreeBSD.org> wrote:

> on 04/04/2013 19:05 Kevin Day said the following:
> [a lot]
> 
> One link: https://wiki.freebsd.org/AvgZfsDeadlockDebug


Sorry, should have mentioned i've seen this.

I've tried procstat, but i've failed at keeping it cached long enough to use it when this happens. If I try running it, the shell gets stuck in 'ufs'. I'm going to add a cron job to just run procstat periodically so hopefully i can run it without it needing to touch the disks.

I built a more debug friendly kernel and tried to drop to ddb when this happened, but it didn't provide anything useful. When I hit 'enter' on 'alltrace' it hard locked without printing anything.

I haven't been able to trigger a core dump, and this system has no serial or firewire ports for live debugging.