my hosting facility replaced disk /dev/sda for me and I've added it to the RAID via
sgdisk -R /dev/sda /dev/sdb
mdadm /dev/md0 -a /dev/sda1
mdadm /dev/md1 -a /dev/sda2
mdadm /dev/md2 -a /dev/sda3
cat /prod/mdstat
looks fine to me:
Personalities : [raid1] [raid0] [raid10] [raid6] [raid5] [raid4]
md2 : active raid1 sda3[0] sdb3[1]
729952192 blocks [2/2] [UU]
md1 : active raid1 sda2[0] sdb2[1]
524224 blocks [2/2] [UU]
md0 : active raid1 sda1[0] sdb1[1]
2096064 blocks [2/2] [UU]
But when I reboot it doesn't work. When I do a grub-install /dev/sda
it says
/usr/sbin/grub-setup: warn: This GPT partition label has no BIOS Boot Partition; embedding won't be possible!. /usr/sbin/grub-setup: error: embedding is not possible, but this is required when the root device is on a RAID array or LVM volume.
When I try a grub-install /dev/sda1
it says
/usr/sbin/grub-setup: error: unable to identify a filesystem in hd0,gpt1; safety check can't be performed.
Do I miss a step to get sda back to boot?