Disk performance is measured in Input/Output per Second (IOPS). One disk read request or one disk write request is equal to one I/O.
The IOPS required to support an application is calculated based on the percentage of read I/O, the percentage of write I/O, and the write penalty of the RAID level the workload will be hosted on.
To calculate the IOPS requirements, perform the following steps:
Determine the number of IOPS a workload requires.
Identify the percentage of read I/O to write I/O for the workload.
Determine the write penalty of the RAID level that will host the workload.
Calculate the IOPS the storage must be capable of providing to support the workload.