I have removed a Sun-supplied 72GB SAS disk (c0t1d0) from our T2000's
zpool, so I can use it as a mirror for the Sun-supplied 72GB system
disk (c0t0d0).

However, somehow the now-spare disk seems to have got an EFI label and
not a VTOC one. This is causing the format program to report the slice
sizes quite differently (cylinders in VTOC, start+end sectors in EFI)
and now even though prtvtoc says the slices I'm trying to mirror are
the same size, metattach fails and metastat says they're different
sizes :-(

It seems like one way to resolve this would be to put a VTOC label on
the disk, but it isn't clear to me how, as I don't know the drive's
geometry or anything.

Does anyone have any suggestions?

Cheers,

Chris