Best Raid Type for SQL Server

Hands down if you needs lots of I/O you need to look at raid 10

RAID 1+0 (or 10) is a mirrored data set (RAID 1) which is then striped (RAID 0), hence the "1+0" name. A RAID 1+0 array requires a minimum of four drives: two mirrored drives to hold half of the striped data, plus another two mirrored for the other half of the data. In Linux MD RAID 10 is a non-nested RAID type like RAID 1, that only requires a minimum of two drives, and may give read performance on the level of RAID 0.

You need three volumes, each on a separate array and if possible, each on a separate controller (assuming the IO volume warrants this).

The first volume should be a RAID 10 volume consisting of as many fast 15k spindles as you can afford, this will be where you data device is stored.

The second volume should be a RAID 1 volume (or raid 10 if you need the space) consisting of fast 15k disks, this will be the volume where your logs are stored.

The third volume should be RAID 1 (or raid 0 if you like living dangerously and can afford the downtime) of fast 15k disks where your temp device is stored.