An administrator wants to check the performance metrics for the workloads and their virtual disks...

Some tools allow for measuring latency peaks. This unfortunately isn't ideal, as it can unfairly represent statistical outliers, which may very well occur when there is little to no I/O activity. The best way to understand the actual behavior of VM and application latencies is to observe in time based performance graphs. Depending on the level of detail, you may need to measure at the individual VMDK level. Become familiar with these graphs to determine what is normal, and what is not for that given application. This is where you can use built-in functionality of vCenter and the vSAN performance service metrics to gather this information.