Re: RAID extremely slow

[Kevin Ross]

> > > unused devices:<none>
> > >
> > > # cat /proc/sys/dev/raid/speed_limit_min
> > > 10000
> > MD is unable to reach its minimum rebuild rate while other system
> > activity is ongoing.  You might want to lower this number to see if that
> > gets you out of the stalls.
> >
> > Or temporarily shut down mythtv.
>
> I will try lowering those numbers next time this happens, which will 
> probably be within the next day or two.  That's about how often this 
> happens.

Unfortunately, it has happened again, with speeds at near zero.

# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid6 sdh1[0] sdd1[9] sde1[10] sdb1[6] sdi1[7] sdc1[4] 
sdf1[3] sdg1[8] sdj1[1]
      6837311488 blocks super 1.2 level 6, 512k chunk, algorithm 2 
[9/9] [UUUUUUUUU]
      [=>...................]  resync =  8.3% (81251712/976758784) 
finish=1057826.4min speed=14K/sec

unused devices: <none>

atop doesn't show ANY activity on the raid device or the individual drives.
http://img687.imageshack.us/img687/2913/screenshotfrom201207252.png

Also, I tried writing to a test file with the following command, and it 
hangs.  I let it go for about 30 minutes, with no change.

# dd if=/dev/zero of=test bs=1M count=1

dmesg only reports hung tasks.  It doesn't report any other problems.  
Here's my dmesg output:
http://pastebin.ca/2174778

I'm going to try rebooting into single user mode, and see if the rebuild 
succeeds without stalling.

-- Kevin

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/