When the Oracle DBAs ask for disks, they always specify that they want XXXX IOPs.  For example, I got a request today for 3 TB (20 LUNs x 150 GB) of space which must support 4500  IOPs.  RAID 5 (4+1).

So, how do I calculate this?

If it's RAID 5 (4+1), and the IOPs of the disk 180 IOPs per disk (15K RPM, 4 Gb/s). Do I count ALL of the disks, including the parity disk, or do I just count the "data disks".  i.e. - If I have 1 RAID Group R5(4+1) is that 4 x 180 IOPS/disk ro 5 x 180 IOPS/disk?

If the disks are RAID 1/0, do I count ALL of the disks, or just 1/2 of the disks?

   Stuart