There are two ways to copy the partition layout from one drive to another - Using prtvtoc/fmthard or via the dd command:

Using prtvtoc/fmthard:

# prtvtoc /dev/rdsk/c0t0d0s2 | fmthard -s /dev/rdsk/c1t0d0s2 


where:  c0t0d0s2 is the source disk
        c1d0s0s2 is the target disk

Using the dd command:

# dd if=/dev/rdsk/c0t0d0s2 of=/dev/rdsk/c1t0d0s2 bs=512 count=16


where:  c0t0d0s2 is the source disk
        c1d0s0s2 is the target disk