On the Task Manager Performance tab we can see real-time server performance, namely processor, memory, and network performance. What is missing; The performance metrics of the disks.
By changing the Task Manager on Windows Server 2012 and then on Windows Server 2016, Microsoft chose to remove this from the Task Manager because it had significant performance implications when collecting the metrics for each process/thread of the disks. Instead, they suggest using the Resource Monitor to display performance and measurement of drives.
The Disk Counter has been removed from the Performance tab in Windows Server 2012. This is because there is a significant performance impact to collect Disk metrics on a Server due to the overhead Task Manager may cause in querying each Disk IO for each process/disk. Disk metrics are very useful while troubleshooting performance issues on the server. An easy way to check Disk metrics is to use Resource Monitor. Source
In fact, for the same reason, the corresponding disk and network columns have also been disabled from the Processes tab of the Task Manager.
However, you can enable disk performance in Task Manager with a simple command at the command prompt. This method applies to both Windows Server 2016 and Windows Server 2012 and R2.
Show disk performance metrics in Task Manager
Open the command line (cmd) with administrator permissions and click on the following command:
That’s it. Reopen a Task Manager window and you’ll see that your server’s disk performance is now showing up.
To disable this feature at any time, simply type the following command at the command line with administrator privileges.