How to prevent high paging on certain Windows versions?
This blog discusses a specific paging performance issue on Windows Server 2012, 2012 R2, 2016 and 2019.
If you operate a SAP ABAP Dialog Instance on Windows you maybe experience a very high paging rate (write operations).
Here is an example from Windows Resource Monitor:
Do you notice the orange bar? It displays the modified memory pages, which will be soon written to the pagefile, due to memory optimization of the Windows kernel.
You can see this type of paging in Disk tab of Resource Monitor:
The Windows kernel itself (System PID 4) writes with 208 Mbyte/sec to the Pagefile, in this example on c:\pagefile.sys. You may notice, that the priority for this is “Background I/O”.
Even it is background I/O it will cause bad performance issues!
The solution for this behavior was delivered by Microsoft with the July 2019 patches for
Windows Server 2012 R2
Windows Server 2016
Windows Server 2019
Microsoft does not fix this behavior in Windows Server 2012!
Windows 2008 R2 is not affected!
To get rid of the above described paging problem, you must do two things:
- Install the patches of July 2019 (or later) via Windows Update
- Set a registry key value to enable the patch (requires reboot of the OS)
Add this value via Registry Editor (regedit) or using PowerShell commands:
If the patch is working, you do not see any high page writes to the Pagefile in Windows Resource Monitor anymore.
What you see, is a background I/O to Pagefile.sys of ~ 1 Mbyte/sec with a very strange high response time (more than a second!). This indicates, that the patch Microsoft created to prevent the high page writes to pagefile.sys, is working properly.