Windows VM's memory management compatibility: Let's make Windows memory management better!

[Petros]

Hello Proxmox Community,

I am addressing a longstanding and widely experienced issue where memory freed by the VirtIO balloon driver in Windows VMs isn't reflected in the Proxmox host's memory usage statistics. Despite successful ballooning shown within the VM, the host reports full RAM allocation.

Environment Details:

• Proxmox VE Version:7 to 8.2.2
• VM OS: Windows Server 2019-2022
• Memory Allocated: 12 GB
• VirtIO Drivers Version: 0.1.248-0.1.240 (issue persists across all versions)

Symptoms:

• Reduced memory usage shown in both Windows Task Manager and Proxmox VM graph.
• Proxmox host continues to report full 12 GB usage.

Expected Behavior:Host memory statistics should accurately reflect the memory in use after ballooning, showing only the utilized amount.

Concerns:This enduring issue suggests potential challenges on the Proxmox/host side. The ongoing nature of this problem, despite various VirtIO driver versions, indicates a deeper compatibility issue. We need to resolve this to allow Windows users to effectively use ballooning features.

This problem has persisted for too long, and it's time to find a resolution that allows all users to benefit from the intended functionality of memory ballooning. Any insights, shared experiences, or potential solutions would be greatly appreciated!

Thank you for your support in resolving this issue.

Best regards,
Petros

 

[Petros]

bump

 

[BobhWasatch]

My solution is to not use Windows.

 

[leesteken]

• Reduced memory usage shown in both Windows Task Manager

Maybe the developers of the Windows VirtIO (balloon) driver have some influence on this, but I would no be surprised if you need to contact Microsoft about that.

• Reduced memory usage shown in [...] Proxmox VM graph.

I'm sure Proxmox could hide this memory or show it separately (providing some patches to do this might speed things up) but they have little influence on software inside VMs.

 

[Petros]

My solution is to not use Windows.

Hah, thats not a solution.

 

[BobhWasatch]

It is for me.

 

[Petros]

Maybe the developers of the Windows VirtIO (balloon) driver have some influence on this, but I would no be surprised if you need to contact Microsoft about that.

I'm sure Proxmox could hide this memory or show it separately (providing some patches to do this might speed things up) but they have little influence on software inside VMs.

Thank you for your response. From my observation, VirtIO ballooning does its job well inside Windows VMs, as the memory is reported to be freed by the VM itself. However, the Proxmox host doesn't seem to reclaim this memory accordingly. I wonder if it's a reporting issue or if Proxmox can adjust how memory is shown/handled on the host side. I agree that Microsoft or VirtIO devs might play a role, but perhaps a Proxmox-side solution could help.

 

[BobhWasatch]

Balloon only reclaims memory from a VM when they system RAM is 80% utilized. It says that right in the manual.

I'm always amazed by two things here in this forum:

1. People assign RAM to a VM and then freak out when it actually uses the RAM they have assigned. Do you expect the same OS to have lots of free RAM on a physical machine? I hope not! Why would it behave differently in a VM?
2. People expect Free Software to fix issues with Proprietary Software. Nobody ever yells about NVidia's shitty drivers or Microsoft's shitty OS. No, it is always PVE or Linux or some developer on the Internet who needs to fix the problems, never the actual maker of the software.

ETA: I get that #2 is mostly because the proprietary software vendors don't listen. But that's a reason to not use their software, not to ask other people to fix it.

 

[Petros]

>

1. People expect Free Software to fix issues with Proprietary Software. Nobody ever yells about NVidia's shitty drivers or Microsoft's shitty OS. No, it is always PVE or Linux or some developer on the Internet who needs to fix the problems, never the actual maker of the software.

Is it because we suspect the issue could be from Proxmox-end?

>
ETA: I get that #2 is mostly because the proprietary software vendors don't listen. But that's a reason to not use their software, not to ask other people to fix it.
And, yes you have answered your question.