combining drive space into one big space

[David Foster]

Ok I got questions,
 I have been running mythtv on Ubuntu for three months and am running out of
hard drive space :)  It chews up about 2 gigs an hour then if it has
enough free space it transcodes them down to 650megs and hour.
 I have one 40g drive with a 30gig partition devoted to recorded
shows, mounted as /myth , the others, /root /cache and swap ocuppy the
rest. So /myth in now almost full and I have in my hand a extra 30gig
hard drive that I plan to stuff in.
 My question is, can I combine the exsisting 30gig /myth with the new
drive(after I freshly format it) to make one big 60g /myth. I was
thinking possibly a configuring them in an array? or can I just mount
them both as /myth and let the files fly.
 One sticking point may be that I don't really want to loose the
27gig of shows that are on there right now.
 Any suggestions would be appreciated( know, fork out the money and
buy a bigger drive).
-- 
David Foster
dbfoster at gmail.com

Ubuntu/Hoary
Durron 687/256m/40g/gforce440/wintvGo/packard bell remote (your basic
getto system :)