powersupport

Active Member
Jan 18, 2020
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Our proxmox VE single node with ZFS (2x 4TB HDD) is showing very high memory usage. However, I have already limited the usage to "8GB" for ARC. Inside VM, when the memory usage is only 2-3 GB, the VM status on PVE is also showing correct values. However, PVE Node shows very high memory usage (About 37 GB) but nothing is being used actually. Please find the screenshots.

mem.PNG

mem2.png

mem3.png

mem4.PNG

The high memory usage is resolved when this VM is in a shutdown state. Please help me to resolve this.:(
 
You assign 32 GB to the VM and now complain that it is used on the host?
I don't understand your concern.
Why would you assign that much memory anyways if you are not planning to use it?
 
Hi,

Please note that VM is only using around 4 GB of ram. You could see it from the attached image of the task manager. But yet PVE Node shows very high memory usage (About 40 GB) but nothing is being used actually. kindly advice
 
But yet PVE Node shows very high memory usage (About 40 GB)
32 GB from the VM that you have assigned + the PVE OS + likely some caches.
Even if you only see a consumption of 4GB within / for the VM that does not mean the host does not need / consume the memory.

It is a misconception that virtualization comes for free. That's why you only should assign the resources you need. Everything creates overheads in management for the system (for instance ballooning) but as long as the system has resources I don't find it unlogical what you see.
Hence the question: what is exactly your concern or maybe better: what do you actually expect?
 
Thank you for referring to this thread. So this a bug right? May I know disabling Ballooning will fix this issue for Windows VMs? Does disable ballooning means PVE node never know how much memory a VM consumes. Thank you

PVE still knows how much memory the vm consumes.
 
Nevertheless - if it is a bug or not. There is no point in comllaining about memory usage in these cases. If you don't plan to use these large memories then don't assign it.
Everything else will lead to memory pressure and yes, ballooning can help freeing up memory but it will also add overhead and swapping activity.
So best is simply to size appropriate and not with such high headroom.
What does the application need? If it is not 32GB, then don't assign it.
 
Nevertheless - if it is a bug or not. There is no point in comllaining about memory usage in these cases. If you don't plan to use these large memories then don't assign it.
Everything else will lead to memory pressure and yes, ballooning can help freeing up memory but it will also add overhead and swapping activity.
So best is simply to size appropriate and not with such high headroom.
What does the application need? If it is not 32GB, then don't assign it.
It's an ERP application for our client. They require 32 GB server but mostly they use 16 to 20 GB maximum. So I can use the free space for other VMs :)
 
Does it use less memory now ?
Hi, even after enabling the ballooning in windows, the host node still allocates all memory to the guest VM. But in reality, proxmox guest VM summary shows only 4 GB usage and the host node summary shows 34 GB of usage. Any possible solution to this problem?
 
Really shouldn’t over provision resources, in case that one time all the CTs or VMs are needing to use those resources.
 
Thank you for referring to this thread. So this a bug right? May I know disabling Ballooning will fix this issue for Windows VMs? Does disable ballooning means PVE node never know how much memory a VM consumes. Thank you
It's not just balooning. It's doing it with regular ram provision as well.
 
Really shouldn’t over provision resources, in case that one time all the CTs or VMs are needing to use those resources.
It's not even that the ram gets over provisioned, it's that it gets flooded with some kind of leak and you can't do anything after, because you only have some 6 or 7% of your ram left. So where it seems like your OS, is operating just fine. It's not, not until the service realizes that you can't use that ram, and lets it go.
 

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