responsiveness during raid check (Was: Problems with RAID 6 across 15 disks)

[Luca Berra <bluca@comedia.it>]

On Fri, Apr 02, 2010 at 07:43:25AM +1100, Neil Brown wrote:
>On Thu, 01 Apr 2010 15:07:27 +0100
>Max Eaves <max@maxeaves.co.uk> wrote:
>
>> Doug,
>> 
>> Thank you very much for that; a great relief off my shoulders.
>> 
>> You are right - there is a config file located in 
>> /etc/sysconfig/raid-check.  I've changed ENABLED to no.
>
>However there is real value in doing that check, at least occasionally.  It
>catches latent read errors.
>
>You might want to run it only every couple of months, and you might want to
>wind down one of both of the /proc/sys/dev/raid/speed_limit_* numbers so
>there is minimal impact on your system.
>
sorry if i am hijacking, but i got a report from one user that the
scheduled scrubbing is severely impacting responsiveness, lowering the
speed_limits seems to help a bit, but he reports it is still sluggish, 
i always believed the check should use idle time, and not impact
performance that much. could it be scheduler related?

regards,
L.

-- 
Luca Berra -- bluca@comedia.it
         Communication Media & Services S.r.l.
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