lvm snapshots

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

In the guide, I see

  Snapshot feature is not fully implemented in LVM in NetBSD and
  should not be used in production.

A quick try says:

  snapshot: Required device-mapper target(s) not detected in your kernel

Any hints on risking a partial implementation? Or a way of using fss
on a lv?

Cheers,

Patrick