Hi,
I started by mistake a raid as RAID1 with 5 disks when my desire was
to start it as RAID5. Technically, there is no data at all so I could
entirely recreate the raid but this is NOT what I want. I'm taking
this opportunity as an exercise to change a raid level.
The initial state of the raid is:
md9 : active raid1 sda9[0] sdb9[1] sdc9[2] sdd9[3] sde9[4]
5846755328 blocks super 1.2 [5/5] [UUUUU]
bitmap: 0/44 pages [0KB], 65536KB chunk
# I tried to change the level with:
mdadm /dev/md9 --grow --level=5
# But got the error :
mdadm: Impossibly level change request for RAID1
# I followed a howto and did:
# Fail and remove one disk and reduce the size of the raid:
mdadm /dev/md9 --fail /dev/sde9
mdadm /dev/md9 --remove /dev/sde9
mdadm /dev/md9 --remove /dev/sde9
# The status is now
/dev/md9:
Version : 1.2
Creation Time : Thu Aug 31 13:21:32 2017
Raid Level : raid1
Array Size : 5846755328 (5575.90 GiB 5987.08 GB)
Used Dev Size : 5846755328 (5575.90 GiB 5987.08 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Wed Nov 15 16:52:42 2017
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Name : rescue.ovh.net:9
UUID : ff7df55b:357263cd:009f3a94:89293230
Events : 24
Number Major Minor RaidDevice State
0 8 9 0 active sync /dev/sda9
1 8 25 1 active sync /dev/sdb9
2 8 41 2 active sync /dev/sdc9
3 8 57 3 active sync /dev/sdd9
# I re-added sde9 hopping it would become spare:
mdadm /dev/md9 --add /dev/sde9
# But surprisingly, sda9 became faulty at the same time:
/dev/md9:
Version : 1.2
Creation Time : Thu Aug 31 13:21:32 2017
Raid Level : raid1
Array Size : 5846755328 (5575.90 GiB 5987.08 GB)
Used Dev Size : 5846755328 (5575.90 GiB 5987.08 GB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Wed Nov 15 17:10:29 2017
State : clean, degraded
Active Devices : 4
Working Devices : 4
Failed Devices : 1
Spare Devices : 0
Name : rescue.ovh.net:9
UUID : ff7df55b:357263cd:009f3a94:89293230
Events : 29
Number Major Minor RaidDevice State
- 0 0 0 removed
<<< What's that?!!!
1 8 25 1 active sync /dev/sdb9
2 8 41 2 active sync /dev/sdc9
3 8 57 3 active sync /dev/sdd9
0 8 9 - faulty /dev/sda9
<<< sda9 is faulty
4 8 73 4 active sync /dev/sde9
# So I removed and re-added sda9 like this:
mdadm /dev/md9 --remove /dev/sda9
mdadm /dev/md9 --add /dev/sda9
# It was succesfully added as spare but I still have a weird line:
/dev/md9:
Version : 1.2
Creation Time : Thu Aug 31 13:21:32 2017
Raid Level : raid1
Array Size : 5846755328 (5575.90 GiB 5987.08 GB)
Used Dev Size : 5846755328 (5575.90 GiB 5987.08 GB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Wed Nov 15 17:34:10 2017
State : clean, degraded
Active Devices : 4
Working Devices : 5
Failed Devices : 0
Spare Devices : 1
Name : rescue.ovh.net:9
UUID : ff7df55b:357263cd:009f3a94:89293230
Events : 31
Number Major Minor RaidDevice State
- 0 0 0 removed
<<< What's that?!!!
1 8 25 1 active sync /dev/sdb9
2 8 41 2 active sync /dev/sdc9
3 8 57 3 active sync /dev/sdd9
0 8 9 - spare /dev/sda9
4 8 73 4 active sync /dev/sde9
# Then I eventually tried again to change the level:
sudo mdadm /dev/md9 --grow --level=5 --raid-devices=5
# But still got the same issue:
mdadm: Impossibly level change request for RAID1
Any clue ?
Regards
-------------------------
Santiago DIEZ
Quark Systems & CAOBA
23 rue du Buisson Saint-Louis, 75010 Paris
-------------------------
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