This will help:
http://slacksite.com/solaris/disksuite/disksuite.php

Important point is that at least two disks will need a free slice, only about 20MB for DiskSuite to use and put 3 copies of the metatstate database in each, DiskDuite requires a minimum of 3 to work and of course you are planning to cope with disk failures!

So amend the above instructions, from:
# metadb -a /dev/dsk/c0t0d0s5
to:
# metadb -a -c 3 /dev/dsk/c0t0d0s5