On Tue, 25 Jun 2024 at 09:32:21 -0700, Russ Allbery wrote:
> Simon McVittie <s...@debian.org> writes:
> > I think the
> > only model that should be used in new systems is to have some concept of
> > a session (like schroot type=file, but unlike schroot type=directory)
>
> I'm not entirely sure that I'm following the nuances of this discussion,
> so this may be irrelevant, but I think type=btrfs-snapshot provides the
> ideal properties for container file systems.
That's another of the "good" schroot types which don't generally cause bugs
like #499014 and #994836. As of Debian 12, I believe the situation is:
Good (session-based): file, btrfs-snapshot, zfs-snapshot, lvm-snapshot
Bad by default, can be good if combined with a non-trivial union-type:
directory, loopback, block-device
Usually a mistake: plain
I mentioned file because it's the only one of the "good" choices that can
works on any system, without a specific filesystem or storage management
mechanism, but the others are fine too if you happen to have the right
filesystem or storage management. If you have enough RAM, the file
backend unpacked into a tmpfs also completely avoids any possible
performance issue involving fsync(), whether in dpkg or elsewhere :-)
I would also suggest not using the "source chroot" associated with one
of the good (session-based) options, and instead re-bootstrapping the
chroot from first principles whenever that's desired.
smcv
