On 17/04/17 10:30, Adam B wrote:
I've got a synology ds1812+
Could have sworn I did raid 6, but md says raid5 (dont recall
personalities pre-failure)
Lost disk 2, was rebuilding and disk 6 crashed.
Booting from a fresh machine, and attempting to discover the arrays
(md125 is the target)
root@ds:~# mdadm --assemble --scan
mdadm: /dev/md/DiskStation:2 assembled from 6 drives - not enough to
start the array.
mdadm: /dev/md/1_1 has been started with 7 drives (out of 8).
mdadm: /dev/md/0_1 has been started with 7 drives (out of 8).
mdadm: /dev/md/DiskStation:2 exists - ignoring
mdadm: /dev/md125 assembled from 6 drives - not enough to start the array.
root@ds:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md126 : active raid1 sda1[0] sdh1[7] sdg1[6] sde1[4] sdd1[3] sdc1[2] sdb1[1]
2490176 blocks [8/7] [UUUUU_UU]
md127 : active raid1 sda2[0] sdb2[7] sdh2[6] sdg2[5] sde2[3] sdd2[2] sdc2[1]
2097088 blocks [8/7] [UUUU_UUU]
md2 : active raid5 sdf3[5]
20478809792 blocks super 1.2 level 5, 64k chunk, algorithm 2
[8/1] [_____U__]
md1 : active raid1 sdf2[0]
2097088 blocks [8/1] [U_______]
md0 : active raid1 sdf1[0]
2490176 blocks [8/1] [U_______]
Attempting to assemble gives the same error:
root@ds:~# mdadm --assemble --force /dev/md125 /dev/sda3 /dev/sdb3
/dev/sdc3 /dev/sdd3 /dev/sde3 /dev/sdg3 /dev/sdh3
mdadm: /dev/md125 assembled from 6 drives - not enough to start the array.
but also yields:
root@ds:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md125 : inactive sda3[8](S) sdh3[7](S) sdg3[6](S) sde3[4](S)
sdd3[3](S) sdc3[2](S) sdb3[9](S)
20478810915 blocks super 1.2
but:
root@ds:~# mdadm --detail /dev/md125
mdadm: md device /dev/md125 does not appear to be active.
I attempt to run:
root@ds:~# mdadm --manage --run /dev/md125
mdadm: started /dev/md125
root@ds:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md125 : active raid5 sda3[8] sdh3[7] sdg3[6] sde3[4] sdd3[3] sdc3[2]
20478809792 blocks super 1.2 level 5, 64k chunk, algorithm 2
[8/6] [U_UUU_UU]
Add back in the disk we were rebuilding (disk 2) before we lost disk 6:
root@ds:~# mdadm --manage /dev/md125 --add /dev/sdb3
When I have a disk kicked out, after a plug out/in I reintroduce it with
# mdadm --re-add /dev/md125 /dev/sdb3
This triggers a recovery which is often very quick (assuming you have a bitmap).
This, of course, does not work when the disk is physically fully dead, a rare event
for me.
[trim]
--
Eyal Lebedinsky (eyal@xxxxxxxxxxxxxx)
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