I currently have a single 2TB HDD with full disk encryption running on 12.04 (initially set up with LVM on 11.10). I want to add another 2TB HDD to the machine with -- ideally -- the following things considered:

1. No *increased* risk of total data loss: I don't want to lose data on both drives if one goes dead.
I presume this means keeping them in separate volume groups...is that correct?

2. I'd like to only type in a decryption password at boot once, if possible.
No idea how this works.

3. Both drives mount at boot (without additional commands having to be run manually)

What do you recommend?

Thanks so much!