This seems to be a little bit more difficult than setting up the usual software RAID as BTRFS handles RAIDs itself. However, the /boot/EFI partition cannot be part of BTRFS as it needs to be FAT-formatted and so has to be created as a separate partition and mirrored using Linux software RAID.
FWIW from https://wiki.archlinux.org/title/EFI_system_partition ... /efi is a replacement for the historical and now discouraged ESP mountpoint /boot/efi
(In reply to Charles Brown from comment #1) > FWIW from https://wiki.archlinux.org/title/EFI_system_partition > ... > /efi is a replacement for the historical and now discouraged ESP mountpoint > /boot/efi references: https://github.com/systemd/systemd/pull/3757#issuecomment-234290236
(In reply to Charles Brown from comment #2) > (In reply to Charles Brown from comment #1) > > FWIW from https://wiki.archlinux.org/title/EFI_system_partition > > ... > > /efi is a replacement for the historical and now discouraged ESP mountpoint > > /boot/efi > > references: > https://github.com/systemd/systemd/pull/3757#issuecomment-234290236 From https://www.freedesktop.org/software/systemd/man/latest/bootctl.html ... ... "It is recommended to mount the ESP to /efi/, if possible."
In this step, we are not going to move the location where the EFI partition is mounted.
ESP mount point recommendation; and RAID discussion ... https://0pointer.net/blog/linux-boot-partitions.html
(In reply to Charles Brown from comment #5) > ESP mount point recommendation; and RAID discussion > ... > https://0pointer.net/blog/linux-boot-partitions.html I am very aware of this. It has however nothing to do with this ticket.
(In reply to Michael Tremer from comment #6) > (In reply to Charles Brown from comment #5) > > ESP mount point recommendation; and RAID discussion > > ... > > https://0pointer.net/blog/linux-boot-partitions.html > > I am very aware of this. It has however nothing to do with this ticket. The mount point thing was new to me. I thought the "RAID discussion" in this blog post may be of some value -- since this bug has RAID in its name :-)
The objective has now changed, because we need to conduct major rewrites of the installer: We will simply support btrfs on mdraid for the time being until there is more traction to justify spending the time on the rewrite.