Problem with CPU and RAM usage.

[BelluX]

Hi,

i have a problem with my PVE, version 6.4-8.

i have installed three Windows 10 machines, VirtIO are installed (version 0.1.185).

Images speaks for themselves.

VM are very laggy and unresponsive but like you see they only running 3GB at least.

How i can investigate this?










top from proxmox's shell:

 

[birdy]

I would start with giving the VMs the resources they actually need and don't throw everything at them what you have

Memory isn't your problem, but your CPU assignment is not optimal (giving all of your VMs 4 CPUs when your host has only 4 physical CPUs) I would start with giving all of your VMs 1 (yes: one) CPU. If you see that your VM is maxing out (on average > 60% or frequently peaking > 90%) you can always add another CPU.

The reason why your host memory is maxing out is that you probbaly are using ZFS for your storage. ZFS takes all the "free" memory for caching. I see the same on my system but is not affecting performance.

Some reading material:
https://www.heroix.com/blog/vmware-vcpu-over-allocation/

 

[Dunuin]

The reason why your host memory is maxing out is that you probbaly are using ZFS for your storage. ZFS takes all the "free" memory for caching. I see the same on my system but is not affecting performance.

Its not all but 50% of all the RAM. So around 12GB in this case.
Each of the VMs is using 4GB (+ overhead) RAM. And Proxmox needs some RAM too, so you are using more RAM than you really have. I would recommend to limit the ARC size to 8GiB.
And if your Win VM is reporting 1.74GiB of 4GiB used it is actually using 4GiB. 1.74GiB for processes and 2.26GiB for disk caching so full 4GiB are in use and not available to the host or other VMs.

And your IO delay is way too high. Looks like your storage is bottlenecking. What does your storage setup looks like?

And you didn't installed the qemu guest agent service or didn't enabled the "use guest agent" checkbox for your VMs.

 

[birdy]

..., so you are using more RAM than you really have.

12Gb for the 3 VMs leaves 12Gb for Proxmox and ZFS (if he is using ZFS). That doesn't sound to bad to me. Well at least not that bad that it causes this kind of performance issues.

And your IO delay is way too high. Looks like your storage is bottlenecking. What does your storage setup looks like?

Yep. A little more info on the system would also be helpful.