Continuing this thread, and focusing on RAID1. I got an HPE Proliant gen10+ that has hardware RAID support. (can turn it off if I want). I am planning two groupings of RAID1 (it has 4 bays). There is also an internal USB boot port. So I am really a newbie in working with RAID. From this thread it sounds like I want /boot and /boot/efi on that USBVV boot device. Will it work to put / on the first RAID group? What happens if the 1st drive fails and it is replaced with a new blank drive. Will the config in /boot figure this out or does the RAID hardware completely mask the 2 drives and the system runs on the good one while the new one is being replicated? I also don't see how to build that boot USB stick. I will have the install ISO in the boot USB port and the 4 drives set up with hardware RAID. How are things figure out? I am missing some important piece here. Oh, HP does list Redhat support for this unit. thanks for all help. Bob On 1/6/23 11:45, Chris Adams wrote: > Once upon a time, Simon Matter <simon.matter at invoca.ch> said: >> Are you sure that's still true? I've done it that way in the past but it >> seems at least with EL8 you can put /boot/efi on md raid1 with metadata >> format 1.0. That way the EFI firmware will see it as two independent FAT >> filesystems. Only thing you have to be sure is that nothing ever writes to >> these filesystems when Linux is not running, otherwise your /boot/efi md >> raid will become corrupt. >> >> Can someone who has this running confirm that it works? > Yes, that's even how RHEL/Fedora set it up currently I believe. But > like you say, it only works as long as there's no other OS on the system > and the UEFI firmware itself is never used to change anything on the FS. > It's not entirely clear that most UEFI firmwares would handle a drive > failure correctly either (since it's outside the scope of UEFI), so IIRC > there's been some consideration in Fedora of dropping this support. > > And... I'm not sure if GRUB2 handles RAID 1 /boot fully correctly, for > things where it writes to the FS (grubenv updates for "savedefault" for > example). But, there's other issues with GRUB2's FS handling anyway, so > this case is probably far down the list. > > I think that having RAID 1 for /boot and/or /boot/efi can be helpful > (and I've set it up, definitely not saying "don't do that"), but has to > be handled with care and possibly (probably?) would need manual > intervention to get booting again after a drive failure or replacement. >