# create a gpt partitioning scheme on /dev/ada0
gpart create -s gpt ada0
# add a very, very small partition for boot
# This begins at block 40 (2M) and is 472 blocks long (236k)
gpart add -t freebsd-boot -b 40 -s 472 -l ssdboot ada0
# set it up to be bootable
gpart bootcode -b /boot/pmbr -p /boot/gptboot -i1 ada0
# now, add the rest of space as a second partion
# if you want, you can specify the size with the -s parameter
# as in '-s 100g' to only use 100G
# For SSD's without TRIM, set at 80% of available space
gpart add -t freebsd-ufs -l ssdrootfs -b 1m ada0
# format the second partition.
# NOTE: the -t option below turns on TRIM for SSD's
# you can remove that if you are not using an SSD
newfs -U -t /dev/gpt/ssdrootfs