for AVC intra i would want my drives set up like this
2) Media drive (2x or more in raid 0, or much larger raid 5,6)
3) export drive same as above but 2 and 3 can be combined in a large (8+) drive array on a good controller
4) external archival/storage (even if you have raid 5,6)
questions 2 and 3 i am not allowed to comment on (Eric will shoot me, wait am i not the boss?) but i will say there is a lot of MYTH floating around.. guys with 5+ drive letters are ill-informed or are left over from many yrs ago advice.
My 3 hard drives to edit AVCHD are configured as...
1 - 320Gig Boot for Win7 64bit Pro and all program installs
2 - 320Gig data for Win7 paging swap file and video project files
When I create a project on #2 drive, the various work files follow,
so my boot drive is not used for the media cache folder and files
3 - 1Terabyte data for all video files... input & output files (*)
(*) for 4 drives, drive 3 all source files & drive 4 all output files
Search Microsoft to find out how to redirect your Windows paging swap file
1) it's not worth striping or putting 2 2TB 7200rmp drives in a RAID0, if significant media playback performance improvement is the goal.
2) PPRO project files and OS swap file should not be on the boot disc
Project files on the Boot disk are OK, if you have the space. Swap file is always on the boot disk, isn't it? You don't have a choice with Mac. But, anyway, that's why you always want adequate free space on your boot disk: for the swap file.
3) media cache files should be on neither the boot disk nor the media disks
Again, if you have space to spare, it's OK to use the boot disk. However, if your media disk is a RAID 0, anything you put there will read and write faster, and therefore that would be my choice.
If all of the above is true, that means at least 4 disks(?)
Not all the above is true. If your needs are for AVCHD, which is HIGHLY compressed low data rate codec, I don't think you even need a RAID. You can probably get by with a boot drive, and a single fast internal drive (or external on eSATA or USB3), unless you expect to do a half dozen layers in real-time, in which case you're going to need a super-fast multi-core CPU more than fast drives, due to the decompression demands from the codec.
AVC-Intra is a more drive intensive codec. I haven't used it yet, but it does 50 or 100Mb/s. If you have a two-7200 drive RAID 0 for media, that's going to give you more options for formats that require more bandwidth.