Freebsd 11.0 - system freeze on intensive I/O

[Gleb Popov]

On Wed, Aug 9, 2017 at 10:11 AM, Gautam <list at execve.net> wrote:

> Hi,
>
> I raised this topic on freebsd-questions where I suspect a bug caused due
> to swapfile usage on FreeBSD.
>
> You could read details in the below thread, but summary is that with using
> a swapfile (not a swap partition) the system freezes on some single process
> intensive I/O. This is 100% reproducible.
>
> http://marc.info/?l=freebsd-questions&m=150088763825675&w=2
>
> I raised a PR - 220971 ; but there are no backtraces / logs etc. that could
> possibly help.
>
> I would like to help narrow this down, but do not know how. Any suggestions
> on how to debug a system freeze and what I need to do ? I could then try to
> reproduce this and collect the needed information - traces etc.
>
> Thanks,
> Gautam
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I also see symptoms you mentioned on my system, but I'm using ZFS. But my
system is very ancient, so I've been taking it as normal behavior. Like you
said, intensive disk IO turns OS completely unresponsive, except pings.