Newbie RAID1 install and management questions

First question would be why do you want RAID-1...

1. Google is your friend, youll only really need to know what it is what its used for and how. What will be covered by a wiki article. How will be covered in your motherboard manual (assuming its onboard RAID implementation)

2. With RAID-1 you wont be making partitions on both drives in the sense that they will show as one. And yes you can still partition as you always would have.

3. If they are that important they should be backed up anyways, bit of a non-issue after me answering 2.

Ok let me get this straight you have one drive now, with an OS installed and you want to add a second disk for RAID-1? If this is true then you will need to wipe the old drive before creating the array (you could image the drive and place it back after creating the array if you want to keep it).

RAID-1 is mirror which means the drive you add will not add more space it will simply mirror the other drive (same data on both drives but appear as one). In general this will slow down read write speeds.

RAID-0 is striping, which places blocks of data on the either disk. This doubles your effective space but is not redundant against drive failure. It will speed up read and write speeds.