From: Neil Brown <hidden> Date: 2006-07-07 22:01:05
On Friday July 7, jpiszcz@lucidpixels.com wrote:
quoted
quoted
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
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
Hey! You're awake :)
I am going to try it with just 64kb to prove to myself it works with that, but then I will re-create the raid5 again like I had it before and attempt it again, I did not see that documented anywhere!! Also, how do you use the --backup-file option? Nobody seems to know!
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!
From: Jan Engelhardt <hidden> Date: 2006-07-11 07:52:23
quoted
Hm, what's superblock 0.91? It is not mentioned in mdadm.8.
Not sure, the block version perhaps?
Well yes of course, but what characteristics? The manual only lists
0, 0.90, default
Use the original 0.90 format superblock. This format
limits arrays to 28 componenet devices and limits compo■
nent devices of levels 1 and greater to 2 terabytes.
1, 1.0, 1.1, 1.2
Use the new version-1 format superblock. This has few
restrictions. The different subversion store the
superblock at different locations on the device, either
at the end (for 1.0), at the start (for 1.1) or 4K from
the start (for 1.2).
No 0.91 :(
(My mdadm is 2.2, but the problem remains in 2.5.2)
Jan Engelhardt
--
From: Petr Vyskocil <hidden> Date: 2006-07-11 09:15:10
quoted
quoted
Hm, what's superblock 0.91? It is not mentioned in mdadm.8.
Not sure, the block version perhaps?
Well yes of course, but what characteristics? The manual only lists
0, 0.90, default
1, 1.0, 1.1, 1.2
No 0.91 :(
AFAICR superblock version gets raised by 0.01 for the duration of reshape, so that non-reshape aware kernels do not try to assemble it (and cause data corruption).
Petr