When setting up a RAID-1 Ubuntu system (i.e. where
/boot are on RAID-1 mirrors) it's unclear to me what Ubuntu's answer is to making the EFI System Partition (ESP, i.e.
/boot/efi) redundant, as well.
There seems to be some support for letting the Ubuntu installer create 2 ESPs and install the files to both of them. But according to this recent bug report it's still unclear how this scheme is supported by regular package updates:
So how do I have to set up the ESP's on the both disks (when aiming for RAID-1 setup with - say - Ubuntu 20.04 LTS) to make them redundant and keep them in-sync for later Ubuntu updates?
The objective here is to still be able to boot that Ubuntu system, i.e. even when one disk dies.
How does my
/etc/fstab (or other relevant) configuration files have to look for such a setup?
For example, when the first ESP is mounted under
/boot/efi where has the second one to be mounted in order to be recognized by Ubuntu package post-install scripts?
And what are the necessary
dpkg-reconfigure/reinstall commands to fix the ESP setup after an installer failed to set up the ESPs correctly?