I have a mdadm software RAID6 that comes up inactive upon each reboot. All its disk are present but shown as spares. How do I make it start operational (active)?
This is it's state after reboot:
cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : inactive sdg[2](S) sdf[1](S) sde[3](S) sdc[5](S) sdb[0](S) sda[4](S)
xxxxxx blocks
unused devices: <none>
again here
sudo mdadm --detail --scan
INACTIVE-ARRAY /dev/md0 metadata=0.90 UUID=xxx
it is not possible just to assemble it, even with --force
sudo mdadm --assemble --scan --verbose
mdadm: looking for devices for /dev/md0
mdadm: /dev/sdg is busy - skipping
mdadm: /dev/sdf is busy - skipping
mdadm: /dev/sde is busy - skipping
mdadm: /dev/sdc is busy - skipping
mdadm: /dev/sdb is busy - skipping
mdadm: /dev/sda is busy - skipping
sudo mdadm --assemble --scan --force --verbose
mdadm: looking for devices for /dev/md0
mdadm: /dev/sdg is busy - skipping
mdadm: /dev/sdf is busy - skipping
mdadm: /dev/sde is busy - skipping
mdadm: /dev/sdc is busy - skipping
mdadm: /dev/sdb is busy - skipping
mdadm: /dev/sda is busy - skipping
But it can be manually assembled after I stop it:
sudo mdadm --manage --stop /dev/md0
mdadm: stopped /dev/md0
sudo mdadm --assemble --scan
mdadm: /dev/md0 has been started with 6 drives.
sudo mdadm --detail --scan
ARRAY /dev/md0 metadata=0.90 bitmap=/media/intent.bin UUID=xxx
I'm on Ubuntu 18.04.1 LTS
4.15.0-36-generic #39-Ubuntu SMP Mon Sep 24 16:19:09 UTC 2018 x86_64 GNU/Linux
mdadm - v4.1-rc1 - 2018-03-22
What I have noticed is that
sudo mdadm --examine /dev/sd[abcefg]
shows /dev/sde missing in the list below. (Only /dev/sde missing in that table for all disks/devices)
Number Major Minor RaidDevice State
this 3 8 112 3 active sync
0 0 8 48 0 active sync /dev/sdd
1 1 8 0 1 active sync /dev/sda
2 2 8 16 2 active sync /dev/sdb
3 3 8 112 3 active sync
4 4 8 32 4 active sync /dev/sdc
5 5 8 80 5 active sync /dev/sdf
