On Mon, Oct 13, 2025, at 7:21 AM, Chris Murphy wrote: >> If you use the right metadata version, it can work with RAID1. But you >> do have to get that right and I don't know if the installer lets you set >> that. > > It used to be allowed. As I understand it a RHEL customer wanted it. > But upstream mdadm said please don't do this because from the firmware > standpoint it is allowed to read and write to the ESP. And md raid > can't detect the different states automatically, it's necessary to run > repair > md/sync_action which ... it has no unambiguous way of knowing > which block is correct so it only updates blocks in one direction, I > forget the rule but man 5 md has it. As in, if it sees a difference > between mirrors it always copies A and overwrites B. So this might sync > your other ESP to the primary, or it might revert the primary, or worse > case is the firmware scribbles on the drives separately and repair > > sync_action is never done and eventually the ESP is corrupted. > > bootupd was at one time looking into how to keep multiple ESPs synced. > But I'm not sure where that is now.
Note that it is still allowed by the installer, at least it is with the Xfce4 version. "It" being the use of MD raid 1 for the /boot/efi partition. I have a sample of that install using the iso image inside of VirtualBox. I would assume that it would not work if you also wanted to dual boot to Windows. I am still on a legacy BIOS install, so have not actually used this, but it does sound like it would be dangerous from what Chris is describing. -- _______________________________________________ users mailing list -- [email protected] To unsubscribe send an email to [email protected] Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/[email protected] Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
