Freebsd 11.0 - system freeze on intensive I/O

[Mark Millard]

On 2017-Aug-9, at 1:35 AM, Gleb Popov <6yearold at gmail.com> wrote:

> 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.
>> 

See bugzilla 206048 for some more information:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=206048


>> 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.

It is a long term, known problem, not new with 11.x
as I understand. No reasonable fix is known as I
understand: it is not a coding error but a design
property.

>> 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.


===
Mark Millard
markmi at dsl-only.net