When you enable Storage I/O Control, ESXi monitors datastore latency and adjusts the I/O load sent to it, if datastore average latency exceeds the threshold.

Launch the vSphere Client and log in to a vCenter Server system.


In the vSphere Client inventory, select a datastore and click the Configuration tab.


Click Properties.


Under Storage I/O Control, select the Enabled check box.


Click Close.

On the Datastores tab, the Storage I/O Control column shows that Storage I/O Control is enabled for the datastore.