Re: Kernel 2.6.17 and RAID5 Grow Problem (critical section backup)

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Sat, 8 Jul 2006, Neil Brown wrote:

> On Friday July 7, jpiszcz@lucidpixels.com wrote:
>>>>
>>>> Jul  7 08:44:59 p34 kernel: [4295845.933000] raid5: reshape: not enough
>>>> stripes.  Needed 512
>>>> Jul  7 08:44:59 p34 kernel: [4295845.962000] md: couldn't update array
>>>> info. -28
>>>>
>>>> So the RAID5 reshape only works if you use a 128kb or smaller chunk size?
>>>>
>>
>> Neil,
>>
>> Any comments?
>>
>
> Yes.   This is something I need to fix in the next mdadm.
> You need to tell md/raid5 to increase the size of the stripe cache
> before the grow can proceed.  You can do this with
>
>  echo 600 > /sys/block/md3/md/stripe_cache_size
>
> Then the --grow should work.  The next mdadm will do this for you.
>
> NeilBrown
>
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md3 : active raid5 sdc1[7] sde1[6] sdd1[5] hdk1[2] hdi1[4] hde1[3] hdc1[1] 
hda1[0]
       2344252416 blocks super 0.91 level 5, 512k chunk, algorithm 2 [8/8] 
[UUUUUUUU]
       [>....................]  reshape =  0.2% (1099280/390708736) 
finish=1031.7min speed=6293K/sec

It is working, thanks!