Hi All,
I was wondering if someone might be willing to confirm what the current
state of my RAID array is, given the following sequence of events (sorry
it's pretty long)....
I had a clean, running /dev/md0 using 5 disks in RAID 5 (sda1, sdb1,
sdc1, sdd1, hdd1). It had been clean like that for a while. So last
night I decided it was safe to grow the array into a sixth disk....
[root@space ~]# mdadm /dev/md0 --add /dev/hdi1
mdadm: added /dev/hdi1
[root@space ~]# mdadm -D /dev/md0
/dev/md0:
Version : 00.90.03
Creation Time : Wed Jan 9 18:57:53 2008
Raid Level : raid5
Array Size : 1953535744 (1863.04 GiB 2000.42 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 5
Total Devices : 6
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Tue Feb 5 23:55:59 2008
State : clean
Active Devices : 5
Working Devices : 6
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 64K
UUID : 382c157a:405e0640:c30f9e9e:888a5e63
Events : 0.429616
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
2 8 33 2 active sync /dev/sdc1
3 22 65 3 active sync /dev/hdd1
4 8 49 4 active sync /dev/sdd1
5 56 1 - spare /dev/hdi1
[root@space ~]# mdadm --grow /dev/md0 --raid-devices=6
mdadm: Need to backup 1280K of critical section..
mdadm: ... critical section passed.
[root@space ~]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 hdi1[5] sdd1[4] sdc1[2] sdb1[1] sda1[0] hdd1[3]
1953535744 blocks super 0.91 level 5, 64k chunk, algorithm 2 [6/6]
[UUUUUU]
[>....................] reshape = 0.0% (29184/488383936)
finish=2787.4min speed=2918K/sec
unused devices: <none>
[root@space ~]#
OK, so that would take nearly 2 days to complete, so I went to bed happy
about 10 hours ago.
I come to the machine this morning, and I have the following....
[root@space ~]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 hdi1[5] sdd1[6](F) sdc1[2] sdb1[1] sda1[0] hdd1[3]
1953535744 blocks super 0.91 level 5, 64k chunk, algorithm 2 [6/5]
[UUUU_U]
unused devices: <none>
You have new mail in /var/spool/mail/root
[root@space ~]# mdadm -D /dev/md0
/dev/md0:
Version : 00.91.03
Creation Time : Wed Jan 9 18:57:53 2008
Raid Level : raid5
Array Size : 1953535744 (1863.04 GiB 2000.42 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 6
Total Devices : 6
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Wed Feb 6 05:28:09 2008
State : clean, degraded
Active Devices : 5
Working Devices : 5
Failed Devices : 1
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
Delta Devices : 1, (5->6)
UUID : 382c157a:405e0640:c30f9e9e:888a5e63
Events : 0.470964
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
2 8 33 2 active sync /dev/sdc1
3 22 65 3 active sync /dev/hdd1
4 0 0 4 removed
5 56 1 5 active sync /dev/hdi1
6 8 49 - faulty spare
[root@space ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
56086828 11219432 41972344 22% /
/dev/hda1 101086 18281 77586 20% /boot
/dev/md0 1922882096 1775670344 69070324 97% /Downloads
tmpfs 513556 0 513556 0% /dev/shm
[root@space ~]# mdadm /dev/md0 --remove /dev/sdd1
mdadm: cannot find /dev/sdd1: No such file or directory [root@space ~]#
As you can see, one of the original 5 devices has failed (sdd1) and
automatically removed. The reshape has stopped, but the new disk seems
to be in and clean which is the bit I don't understand. The new disk
hasn't been added to the size, so it would seem that md has switched it
to being used as a spare instead (possibly as the grow hadn't
completed?).
How come it seems to have recovered so nicely?
Is there something I can do to check it's integrity?
Was it just so much quicker than 2 days because it switched to only
having to sort out the 1 disk? Would it be safe to run an fsck to check
the integrity of the fs? I don't want to inadvertently blat the raid
array by 'using' it when it's in a dodgy state.
I have unmounted the drive for the time being, so that it doesn't get
any writes until I know what state it is really in.
Any suggestions gratefully received,
Steve.
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