About creating a new partition in Lion

[WayCOOL]

Hi!

I'm a newbie with Mac OS X, and I've a question about creating partition.

I want to create a new partition with my MacBook Pro to keep my personal data so that they will be fine and untouched even if I erased Lion system and install a clean one.

I'm wanna know:

- What will I notice during creating a new partition?

- Is it OK for me to choose the "Mac OS Extended" format (not Journaled) partition to just keep my personal data?

- Once new partition created, is it safe to erased the partition where Lion system is on and install a whole new system?

THX a lot!