Memory usage when PBS runs as VM

[Zwitscher_Tom]

On a Proxmpox Virtual Environment 7.4.14 I installed Proxmox Backup Server 2.4-2 as VM.
PVE shows a memory usage of 95% for the PBS VM.
PBS shows a memory usage of 7%.
At PBS the qemu guest agent is installed.
What causes the huge difference in memory usage?

 

[Dunuin]

Did you also enable the QEMU guest agent in the VMs options tab?
What is free -h inside the VM reporting?

 

[Zwitscher_Tom]

Did you also enable the QEMU guest agent in the VMs options tab?
Yes

What is free -h inside the VM reporting?
root@proxmox-backup:~# free -h
total used free shared buff/cache available
Mem: 7.8Gi 189Mi 204Mi 0.0Ki 7.4Gi 7.3Gi
Swap: 3.8Gi 0.0Ki 3.8Gi

The VM has 8 GB RAM

 

[Dunuin]

Then it looks like PBS is showing "available" instead of "free" RAM while PVE is showing the actual "free" RAM.

 

[Zwitscher_Tom]

Is this now a bug or a feature?

 

[Dunuin]

I think a feature, as this is the most useful point of view from the PBS as a client and from the PVE as a hypervisor.
Fro mthe PBS point of view you don'T care how much RAM is free, you want to know how much RAM is available for processes.
From the point of view of the hypervisor you don't care how much RAM the guestOs got available, all you care about is the actual free (!= available) RAM.