[SOLVED] Balooning with ZFS in VM ?

E

Ernie95

Member
Sep 1, 2025
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Hi All,

I understood that balooning of the memory of VM is not adviced if in the VM we manage ZFS. That is my case.

But I read this :

VM Memory Consumption Shown is Higher​


In some situations you might see that the Memory usage of a VM is higher after the upgrade. Maybe even a bit over 100%.

If the VM does not report detailed memory usage, Proxmox VE will show the host's view of the memory usage. With Proxmox VE 9, the accounting of the memory usage on the host has been adapted and takes the memory overhead of the VM into account. Therefore, the percentage may spike to over 100% in some cases.

If the new Host memory usage field is the same as the Memory Usage field in the VM's summary panel, then Proxmox VE was unable to gather the VM's internal memory usage information.

This happens if one of the following conditions applies:


  • The Ballooning Device has been disabled in the advanced memory settings of the VM.This removes the communication channel to gather the guest's internal memory usage information.
  • The guest does not report back any detailed memory usage information.
    • For example, FreeBSD is known to not report memory usage details, which includes popular firewalls like pfSense or OPNsense.
    • If the BalloonService on a Windows guest is not installed or not running.
Click to expand...

I have this issue and when it overpass the max memory, it froze the service in the VM.

Is there a solution ?

Thanks for advice
 
Hi All

I changed the option with ballooning and min = max.
But the summary view of the VM shows always 100.11 % of the use of memory for VM. I understood that ballooning memory helps to solve this also.

BR
 
If you set the minimum equal to the maximum then ballooning cannot take memory away, so it's always at 100% (+overhead).
If you set the minimum lower than the maximum then ballooning can take memory away (when the Proxmox host memory usage is above the threshold) but it might interfere with your VM. It's a delicate balance and there is no negotiation between the VM and the Proxmox host (the host just takes it). Make sure the minimum is high enough for your VM to function. ZFS can be slow to give memory back but I read that the latest version does it quicker (but maybe not quick enough).
 
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