# IOPS or TPS

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To estimate the maximum TPS or IOPS of a RAID array you can use the following formula.

TPS = (NUMBER_DISKS * IOPS_PER_DISK) / (READ_PERCENT + (WRITE_PERCENT * RAID_FACTOR))

An alternate formula to estimate IOPS or TPS of a RAID array:

TPS = NUMBER_DISKS * IOPS_PER_DISK * (R + W) / R + (W * RAID_FACTOR)

The **RAID_FACTOR** is 1 for RAID0 or no RAID, 2 for RAID10, and 4 for RAID5.

Calculating the **IOPS_PER_DISK** is complicated, but for rough estimates you can use the following table

rotational speed: IOPS 5400 RPM: 80 7200 RPM: 100 10000 RPM: 150 15000 RPM: 200