CPU at 100%

Torpion

New Member
Aug 4, 2023
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Hello everyone,

I recently installed Proxmox on a Dell PowerEdge R320 server equipped with 64 GB of RAM and a processor:

8 x Intel(R) Xeon(R) CPU E5-1410 v2 @ 2.80GHz.

On this server, I’ve set up a pfSense VM, along with other VMs that are behind the pfSense firewall. However, I’m experiencing performance issues related to both the network and CPU.

When I perform a bandwidth test, the CPU usage of my VMs goes above 100%, which ends up throttling the network performance.

My pfSense VM has two VirtIO network interfaces: one for the WAN and one for the LAN. My other VMs also use VirtIO network interfaces. I tried changing the network interface of one of my Windows VMs to Intel E1000, but the problem persists.

I also tried setting the VMs’ CPUs to ‘host’, but the result was the same. At first, I thought the issue was related to Windows, so I installed a graphical Debian VM, but the problem persists.

I can’t figure out what’s causing this issue. Do you have any ideas on where the problem might come from?



Thanks in advance for your help!
 
Last edited:
Hello Torpion! I would check the following:
  1. Make sure that virtualization (Intel VT-x and related options) are turned on in the BIOS.
  2. KVM hardware virtualization should be turned on in the VM settings.
  3. In case of Windows VMs, you should install all VirtIO drivers and guest tools, as recommended by the documentation.
Like you said, if you are not interested in migrating the VM to another machine, you can also try setting the CPU of the VM to host, in which case it will use all available CPU features for improved performance. But since you tried this already, I recommend to first check my suggestions above.
 

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