Which of the following describes the theoretical maximum number of operations a disk can perform and is used to denote the disk performance of storage tiers?

IOPS stands for Input/Output Operations Per Second and defines the theoretical maximum throughput of a storage device in terms of discrete read or write operations. It is the primary metric used to compare and tier storage solutions - for example, distinguishing high-performance NVMe drives from slower spinning disk - making it the correct answer for disk performance benchmarking.

QoS (Quality of Service) is a policy framework for prioritizing and managing traffic or workload resources, not a measurement of raw storage performance capacity.

MIPS (Million Instructions Per Second) is a processor performance metric measuring CPU instruction throughput, not storage device performance.

FPS (Frames Per Second) is a video or display rendering metric and is entirely unrelated to storage I/O performance.