Re: Debugging system freezes on filesystem writes

[Marcus Sundman]

On 09.11.2012 01:41, Marcus Sundman wrote:
> On 07.11.2012 18:17, Jan Kara wrote:
> > On Fri 02-11-12 04:19:24, Marcus Sundman wrote:
> > > Also, and this might be important, according to iotop there is
> > > almost no disk writing going on during the freeze. (Occasionally
> > > there are a few MB/s, but mostly it's 0-200 kB/s.) Well, at least
> > > when an iotop running on nice -20 hasn't frozen completely, which it
> > > does during the more severe freezes.
> >    OK, it seems as if your machine has some problems with memory
> > allocations. Can you capture /proc/vmstat before the freeze and after 
> > the
> > freeze and send them for comparison. Maybe it will show us what is the
> > system doing.
>
> t=01:06 http://sundman.iki.fi/vmstat.pre-freeze.txt
> t=01:08 http://sundman.iki.fi/vmstat.during-freeze.txt
> t=01:12 http://sundman.iki.fi/vmstat.post-freeze.txt

Here are some more vmstats:
http://sundman.iki.fi/vmstats.tar.gz

They are from running this:
while true; do cat /proc/vmstat > "vmstat.$(date +%FT%X).txt"; sleep 10; 
done

There were lots and lots of freezes for almost 20 mins from 14:37:45 
onwards, pretty much constantly, but at 14:56:50 the freezes suddenly 
stopped and everything went back to how it should be.


Thanks,
Marcus

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