Proxmox freezing issue

Proxmox Virtual Environment has established itself as a leading open-source platform for enterprise virtualization, combining KVM hypervisor and LXC containers. The release of Proxmox VE 8.2 brought several enhancements and new features, further solidifying its position in the market. However, like any complex software, users have reported encountering specific issues, one of the more common being the freezing problem.

This blog post will walk you through a straightforward solution to this freezing issue by editing the kernel command line and refreshing the Proxmox boot configuration. For other articles about Proxmox, check my blog to understand why I love this hypervisor. Ok, if you are here, it’s probably to find a solution to the freezing issues in Proxmox VE 8.2.

It is to be expected that a new Kernel, probably 6.8.8-1, might fix the root cause altogether.

Understanding the Proxmox freezing issue

Users have reported that Proxmox VE 8.2 sometimes experiences freezing during operations, leading to disruptions in the virtual environment. This issue can be particularly problematic for production systems, where uptime and stability are paramount. The root cause often lies in how the kernel handles certain hardware interactions, specifically with PCIe power management and ATA command queuing. Typically, the system will become unresponsive and even a reboot might fail.

Solution: editing the Kernel command line

To resolve this freezing issue, we need to modify the kernel parameters. The steps outlined below involve editing the /etc/kernel/cmdline file and adding specific parameters to disable PCIe power management and force non-command queuing for ATA.

Step-by-Step Guide

1. Access the Proxmox shell Start by logging into your Proxmox server and opening a shell session. You can do this directly via the Proxmox web interface or using SSH.
2. Edit the Kernel command line Open the /etc/kernel/cmdline file in your preferred text editor. For example, you can use nano or vim nano /etc/kernel/cmdline

3. Add Kernel parameters Append the following parameters to the existing line in the file pcie_port_pm=off libata.force=noncq

Your /etc/kernel/cmdline file should now include these parameters. These settings disable PCIe port power management and force ATA non-command queuing, which helps prevent the freezing issue.

4. Save and Exit Save the changes and exit the editor (for nano, you can press CTRL + X, then Y, and Enter).
5. Refresh the Proxmox boot configuration To apply the changes, run the following command proxmox-boot-tool refresh

This command updates the boot configuration with the new kernel parameters.

6. Reboot the Server Finally, reboot your Proxmox server to apply the changes reboot

What these settings do

The parameter pcie_port_pm=off instructs the Linux kernel to turn off power management features for all PCIe ports. This means that the PCIe ports will not enter low-power states when they are idle, which can be useful for troubleshooting or ensuring maximum performance, but at the cost of potentially higher power consumption which is probably fine for an hypervisor 😉

The parameter libata.force=noncq instructs the Linux kernel to disable NCQ for all ATA devices. This means that the kernel will not utilize the NCQ feature, and read/write commands will be processed in the order they are received rather than being optimized for performance. Native Command Queuing (NCQ) is a technology that optimizes the order of read and write commands on SATA hard drives to improve performance.

Conclusion

After your server reboots, the new kernel parameters should take effect, and you should notice improved stability and no more freezing issues immediately. This solution leverages specific kernel options to address hardware interaction problems that can cause system instability. It should conclude your freezing issues in Proxmox VE 8.2 until the Kernel is permanently fixed.

Proxmox VE is a powerful and versatile platform, and while issues can occasionally arise, the community and documentation provide robust solutions. By following the steps above, you can ensure your Proxmox VE 8.2 environment runs smoothly and reliably.

For more tips and tricks on managing Proxmox VE and other virtualization technologies, stay tuned to our blog. If you have any questions or need further assistance, feel free to leave a comment or reach out to our support team. Happy virtualizing!