On January 22, 2023 12:19:36 PM EST, Wol [off-list ref] wrote:

On 22/01/2023 05:05, H wrote:

quoted

However, going back to the issue of /boot/efi possibly not being

duplicated by CentOS, would not mdadm take care of that automatically?
How can I check?

mdadm/raid will take care of /boot/efi provided both (a) it's set up 
correctly, and (b) nothing outside of linux modifies it.

You can always run a raid integrity check (can't remember what it's 
called / the syntax) which will confirm they are identical.

But if something *has* messed with the mirror outside of linux, the
only 
way you can find out what happened is to mount the underlying
partitions 
(for heavens sake do that read only !!!) and compare them.

A bit of suggested ?light reading for you - get your head round the 
difference between superblocks 1.0 and 1.2, understand how raid can 
mirror a fat partition and why that only works with 1.0, and then 
understand how you can mount the underlying efi fat partitions 
separately from the raided partition.

Read the raid wiki https://raid.wiki.kernel.org/index.php/Linux_Raid
and 
try to get to grips with what is actually going on ...

Cheers,
Wol

Good to know. Thank you.

By the way, I had not set the partition labels when I installed on the new disks and I see that they became localhost:boot etc, all of the labels start with ”localhost:”

Is there any reason I cannot simply use gparted in CentOS to rename them, ie removing the ”localhost:” part” while keeping the second part of each label? I understand that could have been used in fstab but I have not done that.

Any other place they could potentially be used or is the renaming above safe?