found my notes got it

flarcreate -n jumpstart -x /jumpstart/flash /jumpstart/flash/jumpstart.flar

i think this will omit that directory and save it there correct?

correct, although I personally would use a better name than "jumpstart" for your image. maybe something like a version number or something.

although having said that, you can pull the hostname and date out of a flar archive with:

do i need to do this in single user or can i do it from the terminal logged in>?

depends on what's running at the time.

If there are a lot of open files on the system, they could conceivably be corrupted, but I've made flar images of workstations with nobody logged into them, but otherwise fully operational, and haven't had any problems.

For a snapshot backup, it'll be fine to run on a live system. Just cron it for the middle of the night if it's a server.