Step 1: Enabling Disk Performance Counters
Ensure Task Manager is closed.
Launch the Command Prompt using the "Run as Administrator" option.
Enter the following at the Command Prompt:
diskperf -Y
Hit Enter.
Close the Command Prompt.
Re-open the Task Manager.
After running the diskperf command, the ability to view Disk performance statistics on the performance tab should now be visible.
https://blogs.technet.microsoft.com/canitpro/2013/12/02/step-by-step-enabling-disk-performance-counters-in-windows-server-2012-r2-task-manager/