[mythtv-users] Questions about RAID

[OJ]

Hi
I have started to move my music, pictures, and movies to my MythTV
backend server. My backend server is a AMD64 server with 1 250GB HD and
512 MB RAM.

Now I'm starting to worry about all my data. The problem is that it is
starting to become a huge amount of data so normal backup is not an
realistic option for me.

I'm thinking of buying 3 250GB (or maybe 500GB) HD and setting them up
with software RAID.

Questions:
1. Is RAID the only solution for this purpose?
2. Is it possible to expand this RAID array later (insert an extra HD)?
3. My DVD collection will use a lot of HD space. Any suggestions on how
to reduce the file size (divX, ...)?