Hi guys, I'm a new Mac owner. I bought a 2011 15' base couple days ago. Now I have to think about external hard drives. I learned the Mac has an auto backup program called Time Machine so I'll use that. I will use the external HD for computer system backup and RAW/JPEG files. I'm familiar with what RAID does but never tried it before. My plan is to buy two external HD and use RAID mirroring (?) for redundancy. Is that possible?