[lxc-users] zfs snapshot point

[Serge Hallyn]

Quoting Chris Burroughs (chris.burroughs at gmail.com):
> Currently when using lxc-snapshot the snapshot point is the rootfs
> dataset. (so something like /lxc/foo/rootfs)  I'm trying to
> understand why the dataset doesn't also include the config file (so
> /lxc/foo/). Isn't that file also needed to reconstitute a snapshot,
> or is that information duplicated somewhere inside the rootfs?

It's not duplicated inside the rootfs, and on the one hand what you
suggest can make sense.  However, consider that the rootfs of a
system container often can be directly used to boot a full virt vm
(i.e. kvm) or even bare metal host, and consider things like lvm-,
loop-, and qemu-nbd-backed containers.

That's not to say we couldn't make btrfs and zfs behave differently,
but doing that will complicate things at the higher levels, i.e.
toolsets which are using the lxc api to provide containers for
something (a build farm, whatever) when they are switched from one
backing store type to another.

-serge