Which of the following measurements should be used when benchmarking performance between SAN vendors?

IOPS (Input/Output Operations Per Second) is a fundamental performance metric for storage devices, representing the number of discrete read or write operations that a storage system can perform in one second. It provides a direct measure of the storage system's ability to handle transactional workloads, which is crucial for benchmarking SAN performance across vendors.

I/O block size is a parameter that affects IOPS and throughput, but it's not the primary measurement of overall system performance itself.

Random versus sequential I/O writes describes a workload characteristic, not a direct performance measurement of the SAN's capabilities.

Read vs. write ratio describes another workload characteristic and helps define the type of test, but it's not the ultimate performance metric.