Optimizing storage quality of service (SQOS) by dynamically determining and managing optimal queue depth and system capacity

A system comprising:

• a microprocessor;
• and
• a non-transient computer-readable storage medium, comprising computer instructions executable by the microprocessor, wherein the computer instructions are configured to perform a method comprising the steps of:
• determining a first queue depth value;
• processing a first number of I/O requests during a first epoch, wherein
• the first number of I/O requests does not exceed the first queue depth value;
• evaluating the first queue depth value, wherein
• the evaluating the first queue depth value comprises
• determining a first latency value of a storage tier, wherein
• the first latency value indicates an amount of time that is needed to process an I/O request in the storage tier, and
• determining whether a system capacity increased during the first epoch, wherein
• the determining whether the system capacity increased during the first epoch is based, at least in part, on the first latency value;
• and
• in response to determining that the system capacity increased during the first epoch, dynamically determining a second queue depth value.

A computer program product, comprising a plurality of instructions stored on a non-transient computer-readable storage medium, wherein the instructions are configured to execute a method comprising the steps of:

• determining a first queue depth value;
• processing a first number of I/O requests during a first epoch, wherein the first number of I/O requests does not exceed the first queue depth value;
• evaluating the first queue depth value, wherein
• the evaluating the first queue depth value comprises
• determining a first latency value of a storage tier, wherein
• the first latency value indicates an amount of time that is needed to process an I/O request in the storage tier, and
• determining whether a system capacity increased during the first epoch, wherein
• the determining whether the system capacity increased during the first epoch is based, at least in part, on the first latency value;
• and
• in response to determining that the system capacity increased during the first epoch, dynamically determining a second queue depth value.