Re: sw raid5 hungs on resync and high IO load, 2.6.32.23

[Neil Brown <neilb@suse.de>]

On Wed, 27 Oct 2010 09:35:17 +0200
Martin Hamrle <martin.hamrle@nangu.tv> wrote:

> Hi,
> 
> I'm having this issue on several boxes with several configuration.
> One of them is a box with 8 drives attached to ARC-1160 in pass through
> mode and build sw raid5 from these drives. There is also one drive to OS.
> 
> During resync or check and heavy IO load, process tscpd (tscpd is IO
> load maker) hungs, the machine is still alive but there are many blocked
> processes.
> After tscpd hungs, IO load is generated only by resync. In traceback you
> can see blocked processes (ps, htop cat) accessing tscpd cmdline in
> proc. Some tscpd threads is blocked during writing files into fs on
> raid5. Reading these files is also blocking, reading other files in
> filesystem is fast as usual.  This state takes 110 minutes. After that
> all blocked processes continue their work.
> 
> I am not sure what is the reason of the end of the weird state. I think
> the end was caused by starting copying kernel source into array.
> 
> Note that this is first time when hung processes wake up I never wait so
> long.
> 
> I think that it is related to sw raid because I do not see this issue on
> hw raid or on sw raid without resync.
> 
> kern.log contains initial "INFO: task collectd:2577 blocked for more
> than 120 seconds"
>    and two dumps
> echo w > /proc/sysrq-trigger
> 
> log is located http://files.nangu.tv/kernel/kern.log
> Let me know if you need more info.
> 

When I try to access your kern.log I get 

403 - Forbidden


Just include it in-line in the email.

NeilBrown