Re: Still seeing hangs in xlog_grant_log_space

Juerg Haefliger
2012-04-26T12:37:52Z

On Thu, Apr 26, 2012 at 12:38 AM, Dave Chinner <david@fromorbit.com> wrote:
> On Tue, Apr 24, 2012 at 08:26:04PM +0200, Juerg Haefliger wrote:
>> On Tue, Apr 24, 2012 at 2:07 PM, Dave Chinner <david@fromorbit.com> wrote:
>> > On Tue, Apr 24, 2012 at 10:55:22AM +0200, Juerg Haefliger wrote:
>> >> > Alright, then I need all the usual information. I suspect an event
>> >> > trace is the only way I'm going to see what is happening. I just
>> >> > updated the FAQ entry, so all the necessary info for gathering a
>> >> > trace should be there now.
>> >> >
>> >> > http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F
>> >>
>> >> Very good. Will do. What kernel do you want me to run? I would prefer
>> >> our current production kernel (2.6.38-8-server) but I understand if
>> >> you want something newer.
>> >
>> > If you can reproduce it on a current kernel - 3.4-rc4 if possible, if
>> > not a 3.3.x stable kernel would be best. 2.6.38 is simply too old to
>> > be useful for debugging these sorts of problems...
>>
>> OK, I reproduced a hang running 3.4-rc4. The data is here but it's a
>> whopping 2GB (yes it's compressed):
>> https://region-a.geo-1.objects.hpcloudsvc.com:443/v1.0/AUTH_9630ead2-6194-40df-afd3-7395448d4536/xfs-hang/report-2012-04-24.tar
>
> That's a bit big to be useful, and far bigger than I'm willing to
> download given that I'm on the end of a wet piece of string, not a
> big fat intarwebby pipe.

Fair enough.

> I'm assuming it is the event trace
> that is causing it to blow out? If so, just the 30-60s either side of
> the hang first showing up is probaby necessary, and that should cut
> the size down greatly....

Can I shorten the existing trace.dat? I stopped the trace
automatically 10 secs after the the xlog_... trace showed up in syslog
so effectively some 130+ secs after the hang occured.

...Juerg

> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com