I have two disks from an old server that I believe were a mirrored set. I placed them in a new server and tried to do a zpool import but nothing was found. Does that mean the data that was on them previously is lost or is there some way to reconstitute the pool?
May be your old mirror set was a hardware one, not the ZFS. Depends on your HW. Check partitions table with
prtvtoc /dev/rdsk/c#t#d#
if something is there. ZFS can reconstruct its pools no matter what order are disks placed in.