From: jay on

i have a mirrored zfs filesystem, but it's a mirror
of the full disk -- so there's no issues w/ slice
sizes or disk partitioning.

i want to split the mirror and then re-mount the
now "non-operating" part. once i detach the
mirror i can remove the device. all that
goes just fine. (maybe.) i thought the thing
to do would be to come up with a new pool
and try to put the device in there. but that
empties the prior contents of the disk.

this begins to look impossible. is there
something i'm missing?