1. A method comprising: detecting, by one or more computer processors, a timed-out input/output (I/O) operation; identifying, by one or more computer processors, hardware components involved with the timed-out I/O operation, wherein the hardware components include a plurality of types of hardware components; increasing, by one or more computer processors, involve counts of the hardware components; identifying, by one or more computer processors, a plurality of suspicious hardware components based, at least in part, on a hardware hierarchy including one or more types of hardware components, wherein there is at most one suspicious hardware component for each type of hardware component; and identifying, by one or more computer processors, a performance-degrading hardware component from among the plurality of suspicious hardware components based, at least in part, on the involve counts and the hardware hierarchy, wherein the performance-degrading hardware component is in a layer of the hardware hierarchy that is lower than layers including other suspicious hardware components.