I have two GPT formatted disks both starting with EFI partitions and followed by a single physical raid partition. I installed ubuntu-server 16.04 with software raid over these two raid partitions and once it had installed, I cloned the EFI partition from the mounted EFI partition to the unmounted one using
dd if=/dev/sda1 of=/dev/sdb1 and then inserted the second disk into the UEFI boot chain using
sudo efibootmgr -c -d /dev/sdb -p 1 -L "ubuntu2" -l '\EFI\ubuntu\shimx64.efi' so that if a disk broke I would still be able to boot from the other disk.
At some point I did
apt upgrade and noted that grub was updated so I checked which EFI partition was mounted and cloned it to the other using the same dd command as earlier and then rebooted and checked the output of efibootmgr.
I notice that both HD boot entries begin with "ubuntu HD(1, ....". but I was expecting one of them to begin with "ubuntu2" (and maybe "HD(2, ..." ?)
My questions is: What does this output mean? Are these entries both referring to the same disk or to each disk as I expect? To ensure mutual bootability, do I need to delete the entries and then reinsert them as originally?
I'm afraid to shut down the system and remove a disk to test things in case I bring about a lot of downtime by doing something without properly understanding what's going on.
$ sudo efibootmgr -v BootCurrent: 0001 Timeout: 3 seconds BootOrder: 0001,0000,2001,2002,2003 Boot0000* ubuntu HD(1,GPT,ae9a1a9a-1336-4871-a8a8-07cdaf82fc9f,0x800,0xee000)/File(\EFI\ubuntu\shimx64.efi) Boot0001* ubuntu HD(1,GPT,9a770a2c-e8b6-4921-ab2c-4153c3efc8ea,0x800,0xee000)/File(\EFI\ubuntu\shimx64.efi) Boot2001* EFI USB Device RC Boot2002* EFI DVD/CDROM RC Boot2003* EFI Network RC $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 3.7T 0 disk ├─sda1 8:1 0 476M 0 part └─sda2 8:2 0 3.7T 0 part └─md0 9:0 0 3.7T 0 raid1 ├─vg-root 252:0 0 3.7T 0 lvm / └─vg-swap 252:1 0 29.8G 0 lvm [SWAP] sdb 8:16 0 3.7T 0 disk ├─sdb1 8:17 0 476M 0 part /boot/efi └─sdb2 8:18 0 3.7T 0 part └─md0 9:0 0 3.7T 0 raid1 ├─vg-root 252:0 0 3.7T 0 lvm / └─vg-swap 252:1 0 29.8G 0 lvm [SWAP]