/etc/fstab needs the UUID for the filesystem volume; so if you use blkid, find the line with the filesystem type and label you used when you created the file system, and use the uuid listed after UUID= The grub.cfg should have a boot parameter mduuid which makes mdadm in the initramfs aware that it should assemble the array as soon as it can. It ought to be able to discover what it needs from mdadm metadata 1.x from the member drives, but I'm actually not certain of the role the /etc/mdadm.conf plays or whether it needs to be baked into the initramfs these days. You can use 'systemd-analyze blame' to see if any particular unit file is waiting for either the fs uuid or md uuid to appear. If so I'd probably start with just rebuilding the initramfs with a 'dracut -f'. I'd like to believe on-disk metadata can just be discovered automatically but... Chris Murphy