Re: IBM xSeries stop responding during RAID1 reconstruction

[Niccolo Rigacci <niccolo@rigacci.org>]

On Wed, Jun 14, 2006 at 10:46:09AM -0500, Bill Cizek wrote:
> Niccolo Rigacci wrote:
> 
> >When the sync is complete, the machine start to respond again 
> >perfectly.
> >
> I was able to work around this by lowering 
> /proc/sys/dev/raid/speed_limit_max to a value
> below my disk thruput value (~ 50 MB/s) as follows:
> 
> $ echo 45000 > /proc/sys/dev/raid/speed_limit_max

Thanks!

This hack seems to solve my problem too. So it seems that the 
RAID subsystem does not detect a proper speed to throttle the 
sync.

Can you please send me some details of your system?

- SATA chipset (or motherboard model)?
- Disks make/model?
- Do you have the config file of the kernel that you was running
  (look at /boot/config-<version> file)?

I wonder if kernel preemption can be blamed for that, or burst 
speed of disks can fool the throttle calculation.

-- 
Niccolo Rigacci
Firenze - Italy

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