Clean, degraded Raid (Mirror)

Hello,

I have the exact same problem.

I run 2 arrays in my OMV server. One is RAID0 which works fine and shows ''clean'' and a second Mirror one, RAID1 which shows ''clean, degraded''.

RAID1 works OK too but my most important files are in that array so I'm a bit nervous with regards to its degraded state...

The drives in the RAID1 array are 2 X WD RED 4TB.

I'm under the impression that the degrade state has come up after a sudden power loss.

cat /proc/mdstat

Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md127 : active raid0 sdd[1] sdc[0]
976420864 blocks super 1.2 512k chunks

md0 : active raid1 sdb[1]
3906887488 blocks super 1.2 [2/1] [_U]
bitmap: 20/30 pages [80KB], 65536KB chunk

unused devices:

blkid

/dev/mmcblk1p6: SEC_TYPE="msdos" LABEL="boot" UUID="C0F8-560C" TYPE="vfat" PARTLABEL="boot" PARTUUID="32eef3ba-12f6-4212-84e2-5b0d76f4a993"
/dev/mmcblk1p7: LABEL="linux-root" UUID="2554df01-b8d0-41c1-bdf7-b7d8cddce3b0" TYPE="ext4" PARTLABEL="root" PARTUUID="529dbef1-9df3-4bdd-ac34-01de150ad7d8"
/dev/sda: UUID="7e4bee7e-c759-d5e9-3a7c-3b4f29675188" UUID_SUB="7b6b7f61-8872-f687-ffbf-3b896263b623" LABEL="rockpro64:0" TYPE="linux_raid_member"
/dev/sdb: UUID="7e4bee7e-c759-d5e9-3a7c-3b4f29675188" UUID_SUB="4c994784-29f0-2972-bd52-9900cc19108d" LABEL="rockpro64:0" TYPE="linux_raid_member"
/dev/md0: LABEL="RAID1" UUID="fa71c879-fd37-4fe1-8936-e5d730e3ac50" TYPE="ext4"
/dev/sdc: UUID="b1196f1a-4e11-83fc-59f0-41f2cc3e4aec" UUID_SUB="0249ea81-7454-7012-9eed-8ad7df2e9549" LABEL="rockpro64:0" TYPE="linux_raid_member"
/dev/md127: LABEL="RAID0" UUID="b14b3921-f446-4ca6-8d2d-360618d8f1f8" TYPE="ext4"
/dev/sdd: UUID="b1196f1a-4e11-83fc-59f0-41f2cc3e4aec" UUID_SUB="de2dfc68-3105-b22c-6bb9-d5780b1e64d1" LABEL="rockpro64:0" TYPE="linux_raid_member"
/dev/mmcblk1: PTUUID="86a3793b-4859-49c5-a070-0dd6149749ab" PTTYPE="gpt"
/dev/mmcblk1p1: PARTLABEL="loader1" PARTUUID="762eed66-a529-4c13-904d-33b8ff2d163e"
/dev/mmcblk1p2: PARTLABEL="reserved1" PARTUUID="c72e8fa0-8797-4c20-9ebd-3740dcbd03d4"
/dev/mmcblk1p3: PARTLABEL="reserved2" PARTUUID="afc8a236-0220-4f9a-a5ab-016019452401"
/dev/mmcblk1p4: PARTLABEL="loader2" PARTUUID="02cec096-2af6-46de-8007-2637eb8edc15"
/dev/mmcblk1p5: PARTLABEL="atf" PARTUUID="effa07ab-4894-4803-8d36-3a52d1da9f44"

cat /etc/mdadm/mdadm.conf
# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#

# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
# Note, if no DEVICE line is present, then "DEVICE partitions" is assumed.
# To avoid the auto-assembly of RAID devices a pattern that CAN'T match is
# used if no RAID devices are configured.
DEVICE partitions

# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST

# definitions of existing MD arrays
ARRAY /dev/md/rockpro64:0 metadata=1.2 name=rockpro64:0 UUID=7e4bee7e:c759d5e9:3a7c3b4f:29675188
ARRAY /dev/md/rockpro64:0_0 metadata=1.2 name=rockpro64:0 UUID=b1196f1a:4e1183fc:59f041f2:cc3e4aec

mdadm --detail --scan --verbose
ARRAY /dev/md/rockpro64:0 level=raid1 num-devices=2 metadata=1.2 name=rockpro64:0 UUID=7e4bee7e:c759d5e9:3a7c3b4f:29675188
devices=/dev/sdb
ARRAY /dev/md/rockpro64:0_0 level=raid0 num-devices=2 metadata=1.2 name=rockpro64:0 UUID=b1196f1a:4e1183fc:59f041f2:cc3e4aec
devices=/dev/sdc,/dev/sdd

Any help will be greatly appreciated!

Quote from geaves

Just try re adding the drive as the drive is there in blkid

How am I going to do this? There's no option anywhere and the "recover" button is greyed out.

Quote from geaves

So under raid management selecting the raid that's degraded the recover is greyed out? Is this USB?

They are not USB attached. They are SATA.

I'm sorry. My bad. It's not greyed out but if you click the ''Recover'' option, there's no drive or array to choose. Please refer to the attached screenshots.

Quote from geaves

The you'll have to try from the cli assuming it's /dev/sda try mdadm --add /dev/md0 /dev/sda

It started recovering! Thank you s much!

How am I going to prevent this from happening again in the future?

Safe shutdown the server and probably attach it to a UPS?