Hello,
First of all, my apologies if this is explained somewhere; I haven't
been able to find existing documentation about this exact situation.
Yesterday, I added a new (identical) disk to an existing, clean,
8-disk RAID6 array (with XFS), and attempted to grow the array:
# mdadm --add /dev/md0 /dev/sdb1
# mdadm --grow --raid-devices=9 /dev/md0
Over 24 hours later, the reshape is still in the same state as when it
started, i.e. at 0%. Looking at cat /proc/mdstat , no data seems to
have been moved, and the speed is shown as 0K/sec. The "finish"
estimate just keeps increasing. I don't see any process related to
mdadm in top. Unfortunately, I omitted the backup file in the --grow
command.
I'm looking for guidance regarding what to do next. I'm not sure
whether I should wait longer (how long?), or try to re-assemble the
seemingly-intact original array (how do I stop/restart the reshape
cleanly?), or something else. Any advice would be greatly appreciated.
Here's some additional information about the array after the --grow command:
______________________________________________
# mdadm -D /dev/md0
______________________________________________
/dev/md0:
Version : 1.0
Creation Time : Thu Aug 1 12:23:07 2013
Raid Level : raid6
Array Size : 23442098688 (22356.13 GiB 24004.71 GB)
Used Dev Size : 3907016448 (3726.02 GiB 4000.78 GB)
Raid Devices : 9
Total Devices : 9
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Sun Sep 20 16:48:15 2015
State : clean, reshaping
Active Devices : 9
Working Devices : 9
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 128K
Reshape Status : 0% complete
Delta Devices : 1, (8->9)
Name : (redacted):0
UUID : eea59047:120a0365:353da182:6787e030
Events : 35499
Number Major Minor RaidDevice State
0 8 33 0 active sync /dev/sdc1
1 8 49 1 active sync /dev/sdd1
2 8 97 2 active sync /dev/sdg1
3 8 113 3 active sync /dev/sdh1
4 8 129 4 active sync /dev/sdi1
5 8 145 5 active sync /dev/sdj1
7 8 81 6 active sync /dev/sdf1
6 8 65 7 active sync /dev/sde1
8 8 17 8 active sync /dev/sdb1
______________________________________________
cat /proc/mdstat
______________________________________________
Personalities : [raid6] [raid5] [raid4]
md0 : active raid6 sdb1[8] sdg1[2] sdj1[5] sdc1[0] sdf1[7] sde1[6]
sdh1[3] sdi1[4] sdd1[1]
23442098688 blocks super 1.0 level 6, 128k chunk, algorithm 2
[9/9] [UUUUUUUUU]
[>....................] reshape = 0.0% (0/3907016448)
finish=377198019201.6min speed=0K/sec
bitmap: 0/30 pages [0KB], 65536KB chunk
unused devices: <none>
______________________________________________
# dmesg | grep md
______________________________________________
<pre>
[ 4.468239] md: bind<sdd1>
[ 4.477539] md: bind<sdi1>
[ 4.489898] md: bind<sdh1>
[ 4.499959] md: bind<sde1>
[ 4.507908] md: bind<sdf1>
[ 4.534961] md: bind<sdc1>
[ 4.544582] md: bind<sdj1>
[ 4.550060] md: bind<sdg1>
[ 4.642375] md: raid6 personality registered for level 6
[ 4.642378] md: raid5 personality registered for level 5
[ 4.642407] md: raid4 personality registered for level 4
[ 4.644839] md/raid:md0: device sdg1 operational as raid disk 2
[ 4.644843] md/raid:md0: device sdj1 operational as raid disk 5
[ 4.644844] md/raid:md0: device sdc1 operational as raid disk 0
[ 4.644845] md/raid:md0: device sdf1 operational as raid disk 6
[ 4.644846] md/raid:md0: device sde1 operational as raid disk 7
[ 4.644847] md/raid:md0: device sdh1 operational as raid disk 3
[ 4.644848] md/raid:md0: device sdi1 operational as raid disk 4
[ 4.644850] md/raid:md0: device sdd1 operational as raid disk 1
[ 4.645566] md/raid:md0: allocated 0kB
[ 4.646409] md/raid:md0: raid level 6 active with 8 out of 8
devices, algorithm 2
[ 4.646575] created bitmap (30 pages) for device md0
[ 4.647292] md0: bitmap initialized from disk: read 2 pages, set 0
of 59617 bits
[ 4.699645] md0: detected capacity change from 0 to 24004709056512
[ 4.700805] md0: unknown partition table
[ 4.909274] XFS (md0): Mounting V4 Filesystem
[ 5.335425] XFS (md0): Ending clean mount
[ 1642.872936] md0: unknown partition table
[ 1665.183589] md: bind<sdb1>
[ 1665.217944] md0: unknown partition table
[ 1868.222033] md: reshape of RAID array md0
[ 1868.222037] md: minimum _guaranteed_ speed: 1000 KB/sec/disk.
[ 1868.222038] md: using maximum available idle IO bandwidth (but not
more than 200000 KB/sec) for reshape.
[ 1868.222047] md: using 128k window, over a total of 3907016448k.
[ 1868.276409] md0: unknown partition table
[ 2001.573583] md0: unknown partition table
______________________________________________
# mdadm --version
______________________________________________
mdadm - v3.3.1 - 5th June 2014
--
Guillaume Paumier
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