Quoting James Harper (james.harper(a)bendigoit.com.au):
This is kind of OT, but I'm hoping someone here is
familiar with both
Linux and BSD. Is there a BSD equivalent of kpartx, or is kpartx
available for BSD? I'm exchanging emails with someone who is using BSD
and trying to assist in solving a problem, but I know nothing about
BSD.
kpartx and the rest of the multipath-tools are Linux-specific, on
account of dependency on the Linux device-mapper kernel module.
NetBSD includes a port of Linux lvm2tools and libdevmappers together
with a device-mapper kernel driver specially written for NetBSD. See
chap. 17 in
http://www.netbsd.org/docs/guide/en/netbsd.html .
Said port emerged from Adam Hamsik's 2008 work during Google's Summer of
Code and was then merged into mainline.
http://www.spinics.net/lists/dm-devel/msg07264.html
http://code.google.com/p/google-summer-of-code-2008-netbsd/wiki/NetBSD_lvm
(In general, I'm many years out of date on NetBSD, and so probably can't
help you much beyond that. Also, this storage stuff is almost all
outside of my areas of experience, so the above is at the edge of my
competence or beyond it. You be the judge.)