I checked my server and found one drive to be missing:
root@tiefenkaese ~ # lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme1n1 259:0 0 476.9G 0 disk
├─nvme1n1p1 259:2 0 32G 0 part
│ └─md0 9:0 0 32G 0 raid1 [SWAP]
├─nvme1n1p2 259:3 0 1G 0 part
│ └─md1 9:1 0 1022M 0 raid1 /boot
└─nvme1n1p3 259:5 0 443.9G 0 part
└─md2 9:2 0 443.8G 0 raid1 /
root@tiefenkaese ~ # cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active (auto-read-only) raid1 nvme1n1p1[1]
33520640 blocks super 1.2 [2/1] [_U]
resync=PENDING
md2 : active raid1 nvme1n1p3[1]
465370432 blocks super 1.2 [2/1] [_U]
bitmap: 3/4 pages [12KB], 65536KB chunk
md1 : active raid1 nvme1n1p2[1]
1046528 blocks super 1.2 [2/1] [_U]
unused devices: <none>
After a reboot both drives were available again, but the boot partition was missing on the first drive:
root@tiefenkaese ~ # lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1 259:0 0 476.9G 0 disk
├─nvme0n1p1 259:2 0 32G 0 part
│ └─md0 9:0 0 32G 0 raid1 [SWAP]
├─nvme0n1p2 259:3 0 1G 0 part
└─nvme0n1p3 259:4 0 443.9G 0 part
└─md2 9:2 0 443.8G 0 raid1 /
nvme1n1 259:1 0 476.9G 0 disk
├─nvme1n1p1 259:5 0 32G 0 part
│ └─md0 9:0 0 32G 0 raid1 [SWAP]
├─nvme1n1p2 259:6 0 1G 0 part
│ └─md1 9:1 0 1022M 0 raid1 /boot
└─nvme1n1p3 259:7 0 443.9G 0 part
└─md2 9:2 0 443.8G 0 raid1 /
root@tiefenkaese ~ # cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md2 : active raid1 nvme0n1p3[0] nvme1n1p3[1]
465370432 blocks super 1.2 [2/2] [UU]
bitmap: 3/4 pages [12KB], 65536KB chunk
md1 : active raid1 nvme1n1p2[1]
1046528 blocks super 1.2 [2/1] [_U]
md0 : active (auto-read-only) raid1 nvme0n1p1[0] nvme1n1p1[1]
33520640 blocks super 1.2 [2/2] [UU]
resync=PENDING
unused devices: <none>
How do I rebuild the RAID for the boot partition?
