On Sun, Apr 19, 2020 at 6:08 AM Jonathan Billings <billings@xxxxxxxxxx> wrote: > > On Apr 18, 2020, at 16:19, stan via users <users@xxxxxxxxxxxxxxxxxxxxxxx> wrote: > > That was a while ago, and the details are > > vague to me now, but there was a partition for efi, a partition for > > keeping the disk layout, and a backup mbr partition. > > For EFI only systems, you only need an EFI volume (fat32) which is typically mounted to /boot/efi, a /boot partition and a root partition (or LVM PV). I’m not sure if you need /boot anymore or if GRUB2 is smart enough to read LVM. > GRUB has been able to read LVM metadata for quite a long time; but support hasn't extended to supporting the newer features of LVM including now using the md driver for the backend (same kernel code as mdadm uses), and thin provisioning. So yeah, if it's limited to conventional linear LVM, GRUB can boot off that. In fact it can boot from a degraded mdadm raid6 with LVM on top, even if every drive is LUKS encrypted. (LUKS1 for now, LUKS2 support on the way). Also directly supports Btrfs booting, with all the supported compression types, raid5/6 even degraded, and the latest raid1c3 and raid1c4. It's no doubt a long list of things it can't support, but I would not be surprised if the supported list is way longer. Funny enough one thing it doesn't support, and would be difficult to support, is journal replay following a crash. There are cases where if journal replay doesn't happen, the file system metadata doesn't have a correct view of its own state, so boot can fail. Whereas after journal replay, it'll work. Hence, the importance of making the last critical bootloader change atomic, so that there's always a fallback. This was improved quite a lot with recent BLS by default work. -- Chris Murphy _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx 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/users@xxxxxxxxxxxxxxxxxxxxxxx
