A colleague tells me that with Windows 2012 and 2012 R2 it’s no more necessary set a fixed size for the paging file.
“For Hyper-V servers that run Windows Server 2012 or Windows Server 2012 R2, the page file should be left at the default of setting of System Managed. This is per the Hyper-V Product Group”.
This feature is called “Intelligent Automatic Pagefile Setting”.
So the article that I wrote is applicable only for Hyper-V 2008 and 2008 R2.
By default Windows manages the page file. If for some reason the page file is too small, Windows will need to increase the file size. Increasing the file size will cause a lot of disk IO which could affect performance during high workload periods.
To avoid page file size changes Microsoft recommends setting the size of the page file manually with the same minimum and maximum value.
But what I need to set up as min and max values? A common best practice suggest to set a fixed size page file 1.5 times the size of installed RAM.
So that means, if I have an Hyper-V server with 384 GB of ram, I need to set up a 576 GB page file?
No no don’t worry!
Keep in mind that Hyper-V does not use the page file for memory used by VMs, but for the application running on the parent partition might need some virtual memory.
If you run a 384 GB Hyper-V server, you must consider that the majority of RAM memory will be used by VMs and you don’t have to take it in account for the page file calc.
Consider that you must leave at least 8 GB of RAM for the Hypervisor “survival” so a page file of 12/16 GB is fairly enough.