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
Boot2003* EFI Network   RC

$ lsblk
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]

Worked this out, it is explained and answered in my related question: How can I generate/or edit a grub.cfg on each EFI partition that refers to the ubuntu installation on the same physical disk?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.