What metric indicates the average delay from I/O request submission to completion in ESXi?

The average delay from I/O request submission to its completion is best indicated by read/write latency. This metric measures the time taken for a read or write operation to be executed, providing insight into the performance of storage systems in the ESXi environment.

Read/write latency is crucial for understanding the responsiveness of storage in virtualized environments. High latency values can indicate performance bottlenecks, which can affect the overall efficiency of applications running on the virtual machines. This metric allows administrators to identify issues that may arise from slow disk access, helping them take corrective action to optimize storage performance.

In contrast, command queue latency refers more specifically to the time spent waiting in the command queue before the I/O request is processed, rather than the total time for that request to be completed. Throughput measures the amount of data processed in a given time frame, while IOPS (Input/Output Operations Per Second) quantifies the number of read/write operations per second. Although these metrics are important for assessing performance, they do not directly measure the average time taken for I/O requests to be completed like read/write latency does.