Re: RAID1 over RAID0 misbehavior

[mru@kth.se (Måns Rullgård)]

"Guy" <bugzilla@watkins-home.com> writes:

> linux-raid-owner@vger.kernel.org wrote:
>
> > I recently created a RAID1 mirror from two identical RAID0 arrays
> > under Linux 2.6.0.  I was surprised when /proc/mdstat reported a
> > resync speed of 1 MB/s, even though the system was otherwise idle.  I
> > increased the min sync rate in /proc/sys/dev/raid/speed_limit_min to a
> > large value, and was happy to see the resync rate increase to 40 MB/s.
> > It seems to me like something confused the RAID1 layer into thinking
> > there was lots of IO going on in the system.  My guess is that the
> > disk IO generated by the RAID0 is being overlooked by RAID1 as being
> > caused by the resync rather than other system activity.  Whatever the
> > cause, the current behavior is no good.  I have no idea how to fix it,
> > though.
>
> You did not state your max speed setting.
> Did you try to increase the max speed?

The max speed was 200000, and I left it there.  That is also the value
I set min speed to, just to make sure I'd max out the disks.

-- 
Måns Rullgård
mru@kth.se

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