Someone posted something like this earlier... [3:6:306]root@canoe:/u/dgilbert> zpool attach canoe ad8s4d ad4s3d Assertion failed: (?Q), function rv == 0, file /canoe/64/usr/src/cddl/sbin/zpool/../../../cddl/contrib/opensolaris/cmd/zpool/zpool_vdev.c, line 131. Abort trap: 6 (core dumped) ... and the only reply I see is asking the poster to paste the given XML. Since I'm also getting this crash, I will post that here.