> selected probably a 1.2 superblock, instead. Given all that, unless
> someone
> else has a better idea, I am going to go ahead and tear down the array and
> rebuild it with a version 1.2 superblock. I have suspended all writes to
> the array and double-backed up all the most critical data along with a
> small
> handful of files which for some unknown reason appear to differ by a few
> bytes between the RAID array copy and the backup copy. I just hope like
> all
> get-out the backup system doesn't crash sometime in the four days after I
> tear down the RAID array and start to rebuild it.
>
> I've done some reading, and it's been suggested a 128K chunk size might be
> a
> better choice on my system than the default chunk size of 64K, so I intend
> to create the new array on the raw devices with the command:
>
> mdadm --create --raid-devices=10 --metadata=1.2 --chunk=128 --level=6
> /dev/sd[a-j]
No one noticed this was missing the target array. I didn't either until I
ran it and mdadm complained there weren't enough member disks. 'Puzzled the
dickens out of me until I realized mdadm was trying to create an array at
/dev/sda from disks /dev/sdb - /dev/sdj. 'Silly computer. :-)
For anyone who is interested, the array has been created and formatted, and
the file transfers from the backup have begun, plus I have started to write
all the data I suspended from transferring over the last day or so. The
system is also resyncing the drives, of course, so there is a persistent
stream of fairly high bandwidth reads going on in addition to the writes.
See below. So far, nearly 10,000 files have been created without a halt,
and during a RAID resync the system previous would halt with every single
file creation. Forty-two GB out of over 6T of data has been transferred,
and the system is starting on the large video files right now. I have high
hopes the problem may have been resolved. If so, it is almost certain
reiserfs was the culprit, as nothing else has changed except for the
Superblock format and the disk order within the array. 'Fingers crossed.
RAID-Server:/# iostat 1 2
Linux 2.6.26-1-amd64 (RAID-Server) 04/25/2009 _x86_64_
avg-cpu: %user %nice %system %iowait %steal %idle
3.62 0.00 6.58 11.04 0.00 78.77
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 41.00 3440.04 2467.32 19477424 13969924
sdb 41.19 3441.68 2525.79 19486704 14300948
sdc 41.71 3437.65 2533.14 19463912 14342596
sdd 41.62 3445.47 2524.65 19508192 14294540
sde 41.43 3440.61 2467.74 19480680 13972308
sdf 41.24 3441.43 2519.61 19485296 14265996
sdg 41.53 3432.60 2477.87 19435296 14029668
sdh 41.23 3440.57 2528.07 19480416 14313860
sdi 45.09 3443.20 2466.24 19495336 13963796
sdj 45.29 3431.99 2535.49 19431880 14355876
hda 8.56 105.58 89.97 597815 509384
hda1 0.02 0.45 0.00 2540 0
hda2 8.53 104.94 89.92 594160 509104
hda3 0.00 0.00 0.00 6 0
hda5 0.01 0.12 0.05 693 280
md0 103.20 6.34 14438.02 35880 81747792
avg-cpu: %user %nice %system %iowait %steal %idle
11.17 0.00 15.53 35.92 0.00 37.38
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 55.00 3128.00 4872.00 3128 4872
sdb 50.00 2808.00 4256.00 2808 4256
sdc 44.00 2472.00 3664.00 2472 3664
sdd 42.00 2872.00 3920.00 2872 3920
sde 55.00 2280.00 5360.00 2280 5360
sdf 68.00 2128.00 6984.00 2128 6984
sdg 56.00 2808.00 5432.00 2808 5432
sdh 48.00 3072.00 4608.00 3072 4608
sdi 54.00 3456.00 5008.00 3456 5008
sdj 59.00 3584.00 5008.00 3584 5008
hda 23.00 0.00 184.00 0 184
hda1 0.00 0.00 0.00 0 0
hda2 23.00 0.00 184.00 0 184
hda3 0.00 0.00 0.00 0 0
hda5 0.00 0.00 0.00 0 0
md0 307.00 0.00 33936.00 0 33936
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