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On Tuesday, 31 August 2021 20:21:58 BST Neil Bothwick wrote: |
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> On Tue, 31 Aug 2021 14:21:35 -0400, Rich Freeman wrote: |
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> > > If you are multibooting frequently and getting into the UEFI boot |
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> > > menu to change the boot order or running efibootmgr is too much |
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> > > hassle, then a 3rd party boot manager will be useful. Your choice of |
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> > > GRUB, rEFInd, systemd-boot, syslinux, EFI executable image will be |
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> > > installed and loaded/run by the UEFI firwmare from the ESP, with |
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> > > which in turn you will select and load your desired OS. |
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> > |
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> > So, which (if any) of these options supports either: |
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> > |
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> > 1. An EFI partition plus /boot on zfs (with no limitations on pool |
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> > config, ie it can be a root pool). |
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> > 2. An EFI partition that contains everything. |
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> > |
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> > If I want to use grub+EFI with a zfs root it sounds like I'd need TWO |
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> > boot partitions - an EFI partition (FAT32), and a /boot partition |
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> > (anything, but if ZFS it needs to have controlled features). That |
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> > seems even more messy than what I'm doing now. |
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> |
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> systemd-boot and refind both support everything on EFI. I am pretty sure |
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> GRUB does too, but I have no reason to use GRUB with EFI. My setup on |
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> this box is /boot on FAT32 and / (and everything else) on btrfs. I've |
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> also used the same setup with ZFS. |
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Any boot option on a UEFI MoBo requires an 'EFI System Partition' (ESP), |
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formatted as VFAT. The UEFI firmware boot loader will list/load/run any *.efi |
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software stored in the ESP compatible with the UEFI API, whether this is a |
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boot loader, a kernel with an EFI stub, or some .efi diagnostic application. |
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As long as your boot loader of choice, or kernel image and any initrd contains |
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the requisite fs drivers, there will be no problem mounting and accessing |
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whatever root fs needs to be accessed. |
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GRUB contains a number of ZFS modules to do this job (zfscrypt.mod, |
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zfsinfo.mod, zfs.mod) - not sure about the other boot managers. |
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Typical GRUB installations have /boot/efi mounted on the ESP, with the |
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grubx64.efi image on it, while the rest of the files, vmlinuz symlinks, etc. |
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are on the root partition. |
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Please beware, I have not used zfs to date, only btrfs, so the above merely |
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reflects my understanding rather than in depth experience of the difficulty in |
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managing such a setup. |
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