Comment # 22 on bug 931571 from kolA flash

I guess the cleanest solution for this would be a possibility, to set a maximum
disk-usage.
Think of setting a limit of xxx MB or yyy % of disk-space for snapshots. I
guess the technical problem for this would be how to check this limit
dynamically.

E.g. someone deletes some large, no longer needed files to free enough space
for storing other large files at the same time. So at that moment it has to be
realised that old snapshots have to be deleted.

I think this is pretty much the behaviour needed for a usual enduser (who maybe
doesn't know anything about snapshots). So such a limit should be set by
default (e.g. 10% of disk-space).
An experienced user who's counting on snapshots can always disable this limit
and use the already existing ways to limit snapshots and keep an eye on the
free space himself.

Btw.
Maybe related/duplicate?
https://bugzilla.opensuse.org/show_bug.cgi?id=930893