HOW TO SETUP RAID AND A BASIC CONFIGURATION

Clarifications

Is this a server or a workstation? What brand server? or if white-box, what RAID controller?

RAID = Redundant Array of Inexpensive Disks. All RAID levels except for RAID 0 provide some form of redundancy.
RAID 0 = Striping / no redundancy; effective capacity is the combined capacity of all of the member disks
RAID 1 = Mirror, 2 disks, i.e. the second disk is maintained as a duplicate of the first; effective capacity is that of 1 of the disks.
RAID 1+0 = Mirroring with striping, data is striped across half of the disks, and the other disks are maintained as a duplicate of the stripeset; effective capacity is half of the combined member disks.
RAID 5 = Striping with parity, 3 or more disks, data is striped across all disks with a parity stripe. Any member disk can fail and the data is re-calculated on the fly using the parity stripe, until you replace the failed disk and the array is rebuilt; effective capacity is one disk less than the combined member disks.

On most controllers, you assign your disks to a RAID-set and then create the array(s). So if you want to build a RAID 1, assign 2 disks to a RAID-set and then create your logical RAID 1 volume.

To create a RAID 5, assign 3 or more disks and create your logical RAID 5 volume.

As for design, well RAID 1 (or 1+0) and RAID 5 lend themselves to different kinds of read/write patterns. I generally, when building a server, will create a RAID 1 volume for my O/S and Application program files (and transaction logfiles), and RAID 5 for data and database files.

Hope this helps.
--C