Whether the Uefi same ESP partition (/boot/efi) can be mirrored in two separate hard disk for high availability?
Since i have two disks (ex: sda and sdb) and uses raid 1 for the same. But i kept /boot and /boot/efi out of the raid and kept it as separate partition on sda and rest other space used for raid. And second disk sdb fully utilized for raid.
So if in case the hard disk 1 sda fails then the hard disk 2 sdb wont be booted since it doesn’t have /boot/efi.
So how to achieve the high availability for esp partition on rocky9 linux? Please advise.
RAID 1, the mirror, does have – at least with some version of RAID metadata – the filesystem content from the start of a partition just like regular filesystem in partition sans “raid stuff”. Therefore, if you don’t know (or care) about existence of RAID, you can simply (read) access the files. For example, the EFI and GRUB could probably do so.
The above-mentioned raid-ignorant access is fine as long as it is all read and no attempt to write to the filesystem(s).
When you have OS booting, it can very well assemble the mirror arrays and mount the filesystem from the array. It is the operations from running OS that would write to those filesystem, isn’t it? Those obviously have to (and can) do the mirrored writes.
The EFI, when it can’t find the stored entries, should still be able to detect that the remaining disk has ESP and load something from EFI/BOOT/
Disclaimer: all of the above is untested hypothesis.