Let me explain what im trying to do and what hardware i have, and maybe you all can shed some light on it!

i have a macbook pro 2.16 c2d, and a macally FW external with a 200gb HD.

my mbp has a 120gb HD inside.

What id like to do...

setup a raid mirror (raid1?). when im at home boot from the external HD. when i change something on it, its mirrored onto the internal HD. When im on the road, boot from the internal, and when i get home, the internal will sync with the external, while booting from the external. Basically id like each of the drives to sync with the other, with whichever file is more recent i guess.

now ive tried this in the past, and it seemed that when i use either drive, it would have to COPY the entire contents to the other ( when they were both simultaneously connected), this is obviously bad with 50gigs of info, on a daily basis.

i hope you all can understand what im trying to accomplish, and im really hoping it can be done. I have a FW800 enclosure that absolutely feels like it blows the internal sata away in speed, this is part of my reason.

thanks everyone!