If you adjusted the LUN queue depth, change the Disk.SchedNumReqOutstanding parameter, so that its value matches the queue depth. The parameter controls the maximum number of outstanding requests that all virtual machines can issue to the LUN.

Change this parameter only when you have multiple virtual machines active on a LUN. The parameter does not apply when only one virtual machine is active. In that case, the bandwidth is controlled by the queue depth of the storage adapter.

1

In the vSphere Client, select the host in the inventory panel.

2

Click the Configuration tab and click Advanced Settings under Software.

3

Click Disk in the left panel and scroll down to Disk.SchedNumReqOutstanding.

4

Change the parameter value to the number of your choice and click OK.

This change can impact disk bandwidth scheduling, but experiments have shown improvements for disk-intensive workloads.