Since upgraded from OMV 3 to OMV 4 two weeks ago, I ran into all kinds of trouble with my RAID 10 (Mediasonic ProBox 4 Bays via USB to Odroid XU4). The exact same set up ran very stable on OMV 3. Now on OMV 4, RAID failed to activate after reboot. After rebuilding RAID 10, it shows a degraded array (due to “sda removed”). I thought that was the problem and put in a new replacement drive for sda and let sync finish. But, after rebooting OMV 4, lost RAID again for the third time.
It seems like RAID thinks all 4 drives as spare (S):
# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : inactive sdd(S) sdc(S) sdb(S) sda(S)
15627550048 blocks super 1.2
So, I stopped the mdadm and tried to start again, but my attempt to activate it failed saying that I only have 2 drives (I am pretty sure all 4 drives works and the RAID was running as clean right before the reboot):
# mdadm --assemble --scan
mdadm: /dev/md/Red assembled from 2 drives - not enough to start the array.
I am running out of idea to reactivate the RAID again (after a few different approaches based on suggestions on different forums). Wondered if any suggestions folks here can offer.
Thanks in advance!