Memory high consumption in running VMs

[fasi74]

I have just started using PVE in my organization and running number of VMs on my host, everything is fine however what i am observing is all my guests no matter Linux or Windows have a very high memory utilization graph, even when these guests are in idle state and users are not using. the memory is more then 80% always rest of all is fine.

any ideas ? i am running 6.4-4 version.

thanks in advance.

 

[cyagon]

It looks like this, right?


Linux basically goes with a "unused RAM is wasted RAM" policy, it fills the RAM with cache so the system runs smooth as seen here (yellow):


Windows on the other hand is more conservative with RAM compared to linux, but its RAM-usage via proxmox is still seen as "full" if you do not have the virtio-drivers + qemu guest agent installed: https://pve.proxmox.com/wiki/Windows_2019_guest_best_practices

 

[Dunuin]

Jep, if you don't want linux/win to waste RAM don't assign it more RAM than it acually needs: LinuxAteMyRAM.com

 

[spirit]

windows reserve hypervisor the memory at boot, filling memory with zeroes.
if you don't have the qemu-agent, proxmox only display the hypervisor memory side.
if you have the agent, proxmox display the guest inside memory side. (but memory is still reserved on hypervisro).

linux don't reserve memory at boot. but when you read files, it keeping file in his buffer cache. (and can release it if a running application need it)

 

[fasi74]

Thank you for your answers, i understand now, however how are we to moniter in proxmox if our guest requires more ram or not ??

 

[fasi74]

Thank you for your answers, i understand now, however how are we to moniter in proxmox if our guest requires more ram or not ??

I guess through monitering the indiviual VMs then