Accurate reporting of RAM usage for Windows VM

[mkoculak]

I have a Windows VM for which I have set the minimum and maximum RAM with balooning.
I have installed all the software from VirtIO ISO.

In the summary tab of the VM, Proxmox accurately reports RAM usage.
However in the node summary tab, it seems it reports the maximum value from the Windows VM rather than actual usage.
Is this an expected behavior?
Or is their a way to get the accurate overall node RAM usage?

 

[sterzy]

The summary tab for a node should match the output of free -h as it just reports the RAM that is available/in use on the given node. Hence, the memory used will include all memory currently used by the VMs, the OS, PVE and whatever else is running on the node.

I might be misunderstanding you here, sorry if that's the case. Could you maybe try to clarify in that case. Thanks.

Since you said you installed the software from the VirtIO ISO I am assuming that you have installed the ballooning service correctly [1].

[1]: https://pve.proxmox.com/wiki/Windows_VirtIO_Drivers#Installation

 

[mkoculak]

Hi,
yes, I have followed instructions from this link, used the wizard installation and I see Qemu agent working (so I also assume everything went well).

Just to clarify further:
Node summary shows 143GB of RAM in use
Windows VM summary shows 4 out of 128GB in use
Ubuntu VM summary shows 1.5 out of 256GB in use

free -h shows the same info as node summary.
I also checked htop and it shows 128GB are used by Windows VM.

So I am wondering if this is expected - to have the maximum RAM use reported by Proxmox for Windows VM, even if it seems it knows that that VM uses only 4GB out of 128.
Especially, that it is not the case for other linux-based VM that I have.

 

[Dunuin]

Don't get confused with "available" RAM and "free" RAM, they are not the same. See here: LinuxAteMyRam.com

A WinVM with guest agent enabled will show "available" as "free" RAM (so cached data is counted as "free" in the webUI).
A Linux VM with guest agent enabled will show "free" RAM as "free" RAM (so cached data is not counted as "free" in the webUI).
For Unix VMs that isn'T working at all and the memory footprint of the KVM process will be shown.

If I understand sterzy right the node will show "free" RAM as "free" RAM and not "available" RAM as "free" RAMs so this number will represent how much of that physical RAM is actually in use.

 

[mkoculak]

Thanks for the link, did not know about this distinction.

However, as mentioned earlier, the summary tabs for each VM show accurate information (as in: the same as from inside the VM).
The summary tab for the whole node, on the other hand, sums up the maximum RAM value for Windows VM and real usage for Linux VM.

Since all summaries are generated by Proxmox, I was expecting to get a consistent metric - either sum of maximum or sum of real usage. But in this case, summaries on different levels report different things. So I am wondering if this is expected behavior or did I configure something wrong.
I just assumed I can get an overall summary of real usage of RAM for the whole node, since every element is reported correctly in separation.

 

[remorsebelize]

After various days with troubleshooting i have stumbled upon this post and @Dunuin have cleared up a few things for me. Thank you for taking the time. I see now that this post is over 2 years old.. (hopefully i dont get in trouble for bumping this thread )

So apparently ram is used for disk caching, so the values that proxmox reports in the UI (select a VM and view summary) is apparently both for the used ram and the used available ram for disk caching. I have learnt a valuable lesson from all this, and that is to always check free -h directly in the vm/lxc. Imo if proxmox only reported the used RAM for the VM, it would prevent all this confusion around this topic, lol.

 

[remorsebelize]

Before:



After:


Proxmox Node before:

62GB/64GB RAM

Proxmox Node after:

28GB/64GB