12:11 p.m.
Silverblue users have occasionally expressed a desire to snapshot the
"root" subvolume separately from /var so they can rollback "root"
separately from /var content. Since rpm-ostree puts the rpmdb in /usr,
and Btrfs subvolumes have essentially no cost, it's a nice tweak for
these users. So I've put together a self-contained change proposal to
do that.
https://fedoraproject.org/wiki/Changes/VarSubvol4SilverblueKinoite
I've done quite a few such installations already and the installer has
no issue with it, and systemd fstab generator reliably mounts "var" to
/var early enough that there's trouble there. I consistently see the
journal flush to persistent storage *after* /var has mounted which is
what we need. But if anyone can think of additional liabilities, let
me know.
A possible gotcha I'm not certain about, is if the Btrfs autopart
scheme is modified to add a /var mount point, we need to make sure it
only applies to Silverblue and Kinoite. And only applies to the Btrfs
scheme, not LVM or Standard partitioning schemes. If that's too tricky
in the Fedora 36 time frame, then we'll just punt.
Thanks!
--
Chris Murphy