Calculating IOPs of a harddrive
August 4th, 2011 by D in harddrives, howto
Using 15k RPM drive as example
* Divide RPM / 60 seconds
15000/60 = 250 RPS
* Convert 1 to 250 to decimal
1/250 = 0.004 sec / rotation
* Multiply sec / rotation by 1000 ms
0.004 * 1000 = 4ms per rotation
* Divide in half
4 / 2 = 2ms or RD (rotation delay)
* Add 3ms of average seek time
2 + 3 = 5ms
* Add 2ms for latency
5 + 2 = 7ms
* Divide 1000ms by 7ms
1000 / 7 = 142 IOPs
* Those calculs are from Darren Hoch
