Partitioning EFI machine with two SSD disks in mirror

Question

I have two SSD disks, I want to put them in a software mirror RAID.

But whatever I do the OpenSuSe installation keeps telling me that due to the partitioning scheme he won't be able to install the bootloader.

How should I partition the disks? Also what block sizes should I use for the raid?

I tried the following:

ssd1 -> FAT EFI (256MB)
     -> Raid 1/2 mirror swap (4GB)
     -> Raid 1/2 mirror LVM (~50GB)

ssd2 -> empty (256MB)
     -> Raid 2/2 mirror swap (4GB)
     -> Raid 2/2 mirror LVM (~50GB)

LVM  -> root (25GB)
     -> home (~25GB)

Answer 1

So apparently there are several issues and several approaches to handle this.

EFI should be able to handle RAID paritions, but only with metadata <= 1.0

Newer version of metadata are stored on the beginning of the partition (screwing up the filesystem detection).

You can go without extra /boot partition if you integrate the /boot into /boot/efi after the installation.

What I ended up doing was this (two disks, RAID 1):

• create a layout where you have a non-raid, non-lvm /boot/efi
• create an empty counterpart on the other disk (same size)
• create a /boot that is non-lvm (can be raid)
• create the othe partitions (root, home, swap, etc...)
• let the install do it's work
• clone the /boot/efi using dd
  • dd if=/dev/sda1 of=/dev/sdb1
• add an efi record for the clone
  • efibootmgr -c -g -d /dev/sdb -p 1 -L "opensuse" -l '\EFI\opensuse\grubx64.efi'
• using efibootmgr --bootorder change the boot order so that the two opensuse (or whatever your distro is) records are next to each other

Answer 2

I am not that familiar with SUSE but i think that the boot partition always has to be outside lvm.

the kernel loads the lvm module and then can access the lvm-disks but not before. so you need a 500MB /boot partition outside lvm that can hold the kernel image.

As far as i read you need a special bootmanager to be able to boot form EFI:

I am not sure if this is helpful for you, i only found some german ressources regarding efibootmgr and the corresponding manpage man efibootmgr.

.I always avoided EFI so far and changed to normal bios

Answer 3

I don't know of any pre-existing advice regarding ESP on software RAID1; having been asked recently "what if" on ALT Linux forum, I've suggested to put a separate ESP on each disk and maintain the redundacy by hand if it's really needed UEFI way, or just go BIOS way.

Your setup seems reasonable so it's worth to file a bug against YaST bootloader setup module (please provide a link here if you do); in the meanwhile you might try skipping bootloader installation and installing it by hand while having booted some UEFI capable rescue image (e.g. this one if the existing won't do for some reason).

@itconlor: GRUB2 can boot off LVM but UEFI firmware expects EFI System Partition to be a "simple" partition of specific type (see "EFI Disk Structures").