[craftkiller]

FWIW that snapshot system sounds almost the same as zrepl with zfs. The only difference being the zfs snapshots are read-only so you'd have to do a zfs send+recv to a dataset to mount it read/write. That and the defaults for the tiered snapshotting are different (mine is set to a snapshot every hour for the past day and every day for the past 2 weeks but I don't know what the default is).

[nagaiaida]

zfs clone creates a writable dataset initially backed by a snapshot (and will prevent that snapshot from being deleted without first deleting the clone, even if entirely ship-of-theseused out of sharing any data with it)