Calculate the IOPS a workload requires including read and write amplification.
The buffer cache absorbs most reads, so only misses reach storage. Writes amplify instead, because each one touches every index and the write-ahead log. Under-provisioning IOPS causes latency to collapse non-linearly once the queue saturates, which is why headroom matters more here than for throughput.
Database IOPS
IOPS = reads × miss rate + writes × (1 + indexes) × 2, plus headroom
IOPS = reads × miss rate + writes × (1 + indexes) × 2, plus headroom The buffer cache absorbs most reads, so only misses reach storage. Writes amplify instead, because each one touches every index and the write-ahead log.
Under-provisioning IOPS causes latency to collapse non-linearly once the queue saturates, which is why headroom matters more here than for throughput.
This calculator takes 5 inputs: Reads per second, Writes per second, Buffer cache hit rate, Indexes updated per write, Headroom for peaks. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.