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A month or so ago I finally got a system that would correctly install Proxmox VE – my earlier tests didn't produce much progress. That initial test was done on a virtual machine on my laptop. To make matters worse, my laptop runs 32-bit, so I had to run the test under full QEMU virtualization, which made performance terrible. The amazing thing I found then was that a OpenVZ virtual environment actually worked quite well in those challenging situations.

It did definitely whet my appetite to do more experimentation with Proxmox VE. It has loads of interesting features and I was dieing to try it. It wasn't until recently that I had some spare hardware sitting around that would support KVM virtualization (CPU virtual support). I happened to get several systems that I could spare for some testing.

Read on for my impressions of the new 1.5 release of Proxmox VE and how it compares to VMWare ESXi.


Proxmox VE, like VMWare ESX, is a “bare metal” virtualization environment. You can stick in the CD, answer a few questions, and have a system ready to start putting virtual machines on. So, in that respect it looks a lot like VMWare ESXi. In this review I will be comparing only the free version of ESXi, not any of the for-pay add-ons.

Proxmox provides many compelling advantages over VMWare ESXi. These include not requiring MS Windows for the use, ability to manage a whole cluster of machines, live and off-line migrations, and unrestricted access to the underlying systems.


Like VMWare, Proxmox provides full system virtualization via KVM. Completely unlike VMWare, Proxmox also can provide container-based virtuals via OpenVZ. OpenVZ allows for extremely light-weight virtual machines. For example, my test Hardy system was using 5MB of RAM where a similar fully-virtualized system used 150MB.

The management interface for Proxmox works through a normal browser. VMWare ESXi requires a MS Windows-only client. So in that respect Proxmox is a huge improvement.

Proxmox includes a “cluster” mode which causes multiple servers can be managed from a single web page. So in one management page you can see all the virtual machines you manage, all the hosts, and migration between the machines. VMware requires you to run one instance of the management client per host machine. This functionality is available in VMWare, just not in the free version.

In VMWare, if you want to move a guest virtual to another host, you have to export it to the windows management server, then re-upload it to the new host. And this process tends to go rather slowly. Proxmox on the other hand can do a direct migration from one host to another. You can tell it to move the machine from one host to another.

However, online migration does require shared back-end storage. I tested it using NFS. If you use local storage, as we typically do, you have to shut down the guest. It will then sync the disc image over for you, and start the guest on the destination machine. That runs at well better than the speed of VMWare.

To be honest, the VMWare control panel is much better. It provides graphs of recent, historic usage as opposed to only current utilization. The exception with VMWare's console is that the console access to the guest machines is extremely slow. Unusable for anything but what you absolutely can't do via the network (installs, fixing a broken system). That and the inability to manage multiple machines, otherwise the VMWare control panel is more refined and complete.

However, the Proxmox control interface is quite usable.

One of the biggest problems I ran into with the Proxmox control panel is that I couldn't get the console applet to show a high resolution boot screen, like the Ubuntu desktop install screen. Even the text installer shows up slightly cut off. You can access the console via VNC, but this is not enabled by default and requires you to set up a daemon via “netcat” or inetd.

Also, in some minimal testing I did of the live migration, they weren't entirely stable. If the virtual machine was very active, it would do the migration but then the KVM on the destination machine would just start chewing up all CPU time and the guest would never resume. However, on idle virtual machines I experienced basically no problems.

And finally, it's great that Proxmox is really just a Debian Linux system under the hood. You have unrestricted access to the system including shell access, the ability to do management and monitoring without jumping through hoops like you have to in VMWare, etc… It puts you control, where VMWare has been increasingly trying to lock users out.

In Conclusion

Proxmox shows a lot of promise. Even with the few drawbacks, I would say that Proxmox provides a compelling alternative to the free, and in many ways the commercial, VMWare ESXi.

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