On Sat, Sep 19, 2020 at 5:39 AM Neal Gompa <ngompa13@xxxxxxxxx> wrote: > > On Sat, Sep 19, 2020 at 5:48 AM Daniel Pocock <daniel@xxxxxxxxxx> wrote: > > > > > > I noticed another thread about subvolumes already exists, I'm starting > > this one for the very specific topic of installing multiple root > > filesystems as subvolumes > > > > Examples: Fedora 33 in one subvolume, Fedora rawhide in another > > subvolume, Fedora 33 32-bit in another subvolume, maybe RHEL in a > > subvolume too > > > > Can this be supported by the installer? > > > > Can it be supported by grub? > > > > If somebody installs their OS to the top level of their btrfs today, can > > they pivot that into a subvolume later? > > > > All these OS installs would shared some things like /home > > If all the operating systems support working with the same grub and > support Btrfs with the features enabled in the filesystem, yes. > > The only known issue I'm aware of is that Fedora 33 GRUB cannot boot > Fedora 32 or RHEL 8 because the bootloader spec implementation changed > and it no longer supports variables inside of file snippets. Fedora 33 BLS snippets themselves don't use the kernelopts macro. But F33 GRUB does still load the variable if it's present in the grubenv. On a clean install of Fedora 33, the grubenv is replaced with one that doesn't have kernelopts. But you can restore it. I don't know if this can be done reliably with grubby, without somehow affecting the Fedora 33 installation. But if you merely: grub2-editenv - set kernelopts="root=UUID=32291cea-4dee-4e0d-bdf3-813314e2ab10 ro rootflags=subvol=root32 rhgb quiet" Then this variable will be used by Fedora 32 BLS snippets, and not Fedora 33 snippets. What I'm only 90% certain of (or 100% wrong just by accident) is the behavior of kernel updates. In my sample size of one, Fedora 32 kernel updates continue to create the F32 style BLS snippet with macro. Fedora 33 kernel updates create the F33 style BLS without macro. And thus coexist so long as you don't ever do 'grub2-mkconfig' within Fedora 33,thereby obliterating the shared grubenv, wiping out the kernelopts line. -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-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/devel@xxxxxxxxxxxxxxxxxxxxxxx
