Memory claiming disk space

[Republicus]

I don't remember this being discussed or documented nor do I ever recall experiencing or noticing this happen. Maybe it's normal...

Problem:
When I increase the amount of ram in a VM the disk space on the guest's primary hard drive is used/filled by the adjusted amount of change to memory.

Reducing the amount of memory free's the stolen space.

If this is normal I wish I would have known this before now as that will require me to plan differently and accordingly to that adjustment.


More info:
I set up PVE 5.0 system yesterday
I am updated as of today.
Windows 7 x64 guest
qcow2 format
occurs regardless of ballooning set or not.
all virtio drivers are installed (0.1.126)

To replicate:
Adjust the amount of ram on a VM (Windows 7 x64-- tested across multiple VMs)

 

[Alwin]

How big of a difference? To consider that the page file is sized by windows according to the amount of ram.
https://support.microsoft.com/en-us...opriate-page-file-size-for-64-bit-versions-of

 

[Republicus]

Should the pagefile be equal to the size of VM memory?
If I add 10GB RAM my available space on the disk availability decreases by 10GB. I see 1:1

I wasn't expecting that at all. I built a template to deploy linked clones and tried to keep the base image as small as possible with some room for growth. If this is expected I'll just have to plan for that...

 

[Alwin]

Please check out the link I provided, as it has a table on the page file size for the different OS versions. The page file can grow to a multiple of the RAM size.

 

[Republicus]

I read over the information on the pagefile and that seems correct.
Working with physical hardware that would have been just gobbled up and gone unnoticed. With identical cloned VMs I can notice the difference; but I should have thought of that.

I'm considering setting a fixed pagefile size and moving it to different storage. In particular the VM that I'm working with is on stored on a SSD which is valuable space which is why I was alarmed.

Thanks for your attention. Feel free to mark as solved.