DISK - IOPS Calculation

IOPS per disk (assuming a reasonable latency and random access)

SAS (15K RPM) - 175 IOPS

SATA (7.2K RPM) - 75 IOPS

But how to double check if these numbers are ok or not?

Formula:

IOPS Estimated =  1 / (average latency in ms + average seek time in ms)

IOPS Estimated = 1 / ((seek time / 1000) + (latency / 1000))

Let's make a simple test:

SAS - 600GB 15K - Seagate  

Estimated IOPS = 1 / ( ( (average read seek time+average write seek time) / 2) / 1000) + (average latency / 1000)

Estimated IOPS = 1 / ((3.65 / 1000) + (2.0 / 1000) = 1 / (0.00365) + (0.002) = 176.99115044247787610619469026549 - ~ 175 IOPS

SATA - 1TB 7.2K - Seagate

 Estimated IOPS = 1 / ( ( (average read seek time+average write seek time) / 2) / 1000) + (average latency / 1000)

Estimated IOPS = 1 / ((9.00 / 1000) + (4.16 / 1000) = 1 / (0.009) + (0.00416) = 75.987841945288753799392097264438 - ~ 75 IOPS



Thanks
Adarsh Kumar
AK Technosoft Corp.
www.aktechnosoft.com