Best OS for VMware Server 2.0
As promised in my previous article, today I will provide some recommendation on choosing best host operating system for VMware. I personally consider this to be Linux, however for historical reasons I am stuck with a number of Windows-based hosts in our environment, so it is quite easy for me to compare both.
Our Windows-based hosts mostly use Windows Server 2003 as host operating system, while for Linux hosts I’ve chosen the Debian Linux. Yes, I am sure there are a lot of other great Linux distributives. But I am not looking for hard ways, and back in time I fell in love with Debian because it always “just works” and because updating/patching it is a breeze.
To start off, here is the summary table of most important points for my decision to use Linux over Windows.
Best OS for VMware Server 2.0
Cost. I guess no comments are needed here, Linux is free when Windows is not. One thing to keep in mind though is paid support that you may want to buy for your Linux. But if your company requires this, then most likely you would not be looking at free hypervisors anyway 
Host resources footprint. My method of comparing host resources footprint for OS and hypervisor code, involved rebooting the host server, waiting for a few minutes for boot activities to settle down, and then reviewing the host performance statistics using VMware Infrastructure Client. Please review the results below.
VMware Server 2.0 host footprint depending on OS
Enough said, Linux is a clear winner here, providing even lower footprint than ESXi 4.0, and dramatically lower than Windows 2003 based host. Wonder how I was able to achieve such a low resource usage? Bare with me, more on this below.
Requires Linux expertise. Windows clearly does not need one, which is probably why it has been “default” (albeit not the best) choice for most VMware Server installs. In reality though, Linux expertise is not really required either. The deployment is very easy, there are quite a few step-by-steps on the internet which guide you through the installation procedure, leaving little chance to mess up (if for any reason they do not work for you, let me know in comments and I will create and post the working one). And, after deployment is done, management is even easier – because everything can be done from free tools, without having to even touch Linux console. I plan to cover the tools I am using to manage my hosts in the following article.
API performance. If you were not aware, VMware Server 2.0 has “experimental” support for most of the standard VMware APIs. I think it would be safe to assume that with VMware Server 2.0, hypervisor code was originally written and optimized for Linux, by simply taking the corresponding parts from VMware ESX code. In that case, Windows version of VMware Server is probably ported, and evidently this port does not look to be very polished. Here are the results of file copy performance testing using FastSCP (in “agentless”, NFC API mode) on 1GB LAN.
VMware Server 2.0 API performance depending on host OS
Speed of file copy is obviously very important, because it defines the time required to backup (download) and restore (upload) your VM with VMware backup applications. Of course, on Windows you can easily copy files using Windows Explorer and that will give you great speed – but this way, you can only copy powered off VMs. So you get down time for your VMs, and need to do manual scripting to shutdown and startup VMs for backup. So, as long as you plan to use some existing VMware management tools, Linux is really the only option.
Based on all the fact above, I hope you agree with me now that Linux is a much better host OS choice for VMware Server 2.0 deployments. If you feel I did not cover some benefits or drawbacks of either OS applicability, please let me know in comments, and I will be happy to discuss and update this article with more bullet points.
Lastly, couple of my recommendations on the specific Linux distribution I’ve been using (Debian Etch/Lenny).
During the disk partitioning step of the OS setup, you can accept all the default settings – but I recommend separating /home patition (which is where your VMs will be stored) so it does not get fragmented by logs and OS files. Also, consider using ext2 file system for your storage, it is a bit faster than default ext3 file system (no journaling). I found ext2 to be still very reliable for the given workload, having experienced multiple crashes of one of my hosts due to hardware malfunction.
After you are done with partitioning, Debian installation process allows you to choose among different server roles – clear them all, including Standard system role. This way, you will get extremely small resources footprint due to no unneeded services running, as well as better security due to small attack surface. Security is quite important for me, and Debian provides extremely easy way of patching the OS, as well as timely security updates. Also, I found that overall support for Debian is awesome because of immense community behind this distro.
I hope this information was interesting for you, please let me know what you think in the comments?
Wow…it’s very cool to see your comments. I’ve just bought a “big” desktop and I’d like to have different VMs for compatibility sake. I’ve found VMWare server 2 for free so I’d like to give a try. However, I could not install it on the preinstalled Vista Home Premium.
Could you help me out since I’m very green with Linux?
Thx.
sam.
Hello Sam, I guess I need to create the installation guide then. There are quite a few similar guides on the internet, but not sure if there is one covering the full procedure including minimal Linux install.
You should see performance levels using dedicated drives and NIC cards! It surprised me!
Hey Anton,
what about issues regarding security patches etc. for Linux.
Setting up a Linux host itself might not need much expertise and effort.
But AFAIK Linux servers/host in genereal need more care and expertise in terms of maintenance and updates to keep the secure that windows servers/hosts.
Do you agree on that?
Cheers,
John
Hi John, my opinion:
1. Patching Linux is easy even with no UI, at least for my favorite distributive (Debian), basically just one short command. I am not so sure if you can fully patch Windows Server Core installation as easily, with one command, but I have to admit I never researched this. And with UI, both OS take a few mouse clicks to get patched.
2. Linux hosts require more expertise – NO. Linux hosts require different expertise than Windows – YES!
3. Care and maintenance: the same amount. I don’t touch my Windows or Linux boxes at all, everything happens automatically and “just works”. Linux fans like to state that Windows has tons more viruses and so harder to care/maintain, but I did not get a single one since MS Blast on my Windows boxes for all the time either. And I have NO antiviruses on Windows. Just prompt patching and good security, that’s it.
Hello Anton,
thanks for your article — this is a topic I’ve been looking for answers for and your insight has been very helpful.
I have some questions which I hope you can help me with:
1. Does it still hold true today that vmware Server 2 is better than esx(i) 4?
2. If I were to use ubuntu (or another linux distro) with a GUI, would this still be better than Windows?
3. Would a multi-core computer make a better server than one with less cores but higher clock rate?
thanks again.
Hello Lawrence, it’s been almost a year and some thing did change since then.
1. Yes, VMware Server 2 is still better than *free* ESX(i) 4. However, right now VMware now has great deal on VMware Essentials (USD 500 for up to 3 hosts/6 sockets). For a small lab, this is a best choice – no doubt. The cost of this per server is just 10% of hardware cost; but for this you get fully licensed version without showstopping restrictions I have mentioned in my other post about this.
But of course, if you only have 1 host, then you should probably stick with VMware server.
2. Yes, with or without GUI Linux is a best choice due to much better API performance.
3. Multi-core with lower clock rate is definitely what you want to have for your hosts. Generally, you want CPU with higher sum of GHz across all cores. For example, 4 core x 2GHz = 8 GHz, 2 core x 3 GHz = 6 GHz. See, pretty big difference in CPU resources available for virtual machines.