Beginner's question about Raid 0 - Mac

[lightstand]

First I am a completely in the dark about correctly setting up my computer for speed - so please excuse my inexperience as I'm trying to understand this.  I have searched through the archives and read many posts, but am still confused.  Money is a factor so trying to do things the right way verses what I can afford also comes into play.

I have a 2008 MacPro running 10.6 with 24 gigs of ram and four interior hard drives.  Two of those hard drives are strictly for storage of files. The third hard drive has only the OS and applications on it, the fourth hard drive is blank and has been used as the first scratch disk for photoshop.

My question is would it be best to partition the hard drive with the OS/Applications it is 500 GB to a partition of 200 GB with the OS and create a Raid 0 with the 300 GB partition and the forth empty hard drive for a scratch disk? I do understand that the Raid 0 would only see the 300 GB and not the full size of the fourth hard drive - should I then partition that hard drive to create a little bit more normal storage area (say for music files)? So in the end I would have two internal hard drives both partitioned with 300 GB partitions set up in a Raid 0 - does this make sense?

Thanks for any advice and your understanding that I am very inexperienced when it comes to understanding computers.  jeff

[Ken Bennett]

This site will help:

http://macperformanceguide.com/

I don't think you'll see a large speed improvement if you try to use a partition of your boot drive in a raid configuration -- even less so if you are storing your music on the other drive in a different partition (if you are listening to your music at the time.) If you do decide to try this, make sure you use the first partition for scratch -- it uses the outer, fastest part of the drive.

Scratch slows down when the head has to go someplace else to read -- which is why a separate scratch drive can be faster than using the boot drive as scratch (as in a laptop.) Using two drives in a striped RAID for scratch further speeds up the process, since each drive only reads half the info. But I suspect that using raid-0 partitions for scratch on drives that are doing something else at the same time will be slower than just using a single dedicated scratch drive.

[lightstand]

But I suspect that using raid-0 partitions for scratch on drives that are doing something else at the same time will be slower than just using a single dedicated scratch drive.

Thanks that makes a lot of sense and helps

jeff