When and why to deprecate filesystems

> Offsite? Where? :-) For a home system that could be a problem (unless I put a bare drive in the garage...)

You give a drive to a friend you see sometimes and swap it. (I do this with several friends and relatives living at different distances from me.)

You really don't want to use lvm snapshots to do long-term historical backups: IIRC, writes slow down proportional to the number of snapshots in place. For comparison and to see what you can do with an actual automated backup system, I have 9103 backup snapshots currently accessible in my onsite backup (mostly once-every-three-hourly backups of /home). Most of the backups took under a minute to run (and, obviously, happened with no human intervention at all). LVM would grind completely to a halt long before you reached *that* sort of scale.

> I don't plan to clean out my incrementals, unless I'm running short of disk space.

Quite so -- and since bup uses rsync-style deduplication and also compresses the backups, that's going to be a long time.