Virtualization is great. It is very handy to have your complex installations of server software in a Virtual Machine. I do it for years and have only some client tools that do need a complex installation on my host. JDeveloper, SQLDeveloper or Pl/Sql Developer for instance. It enables you to reinstall your laptop and be up and running after having installed your virtualization product. Provided that you backup your VM's of course. Also I have a Windows based VM with some tools for administration purposes.

I started years ago with VMware Workstation 3 to 5.x. But then VMware Server came out. And back then workstation did not provide much extra above Server. And although I had a demo license for Workstation (which ended), Server was for free. Actually the only missing feature in Server I encountered was 'Shared Folders'. But that I solved using (S)Ftp. Under windows it is very convenient to have a FileZilla Server. You could solve it by defining a share in Windows. But I found that that gives some problems when you have multiple copies of a VM running on the same network. Then you have to change your host name, etc. And it is problematic if you have multiple shared open in multiple VM's while your windows account have a regularly changed password. So shared folders as an alternative to FTP is not necessary but very convenient.

Shortly after VMware Server VMware Player came out. But until today it was not possible to create new VM's in Player. And that is a 'must have' to me.

VMware 2.0 was a large step for me since I found it astonishing that the footprint from 1.0 grew by a factor 5! But since VMware dit not keep 1.0 up with the Linux Kernel changes, I did the upgrade. Now I was a pretty satisfied VMware Server user.

But there are two problems now with VMware Server 2.x.:

• VMware Server 2.x does not keep up with the Linux kernel changes either. I upgraded to OpenSuse 11.2, which worked very well. But stepped back to 11.1 since VMware Server did not install with that kernel.
• Since FireFox 3.6 the VMware Console does not work anymore. This is solvable by installing a seperate FF 3.5.9 for VMware usage. But this is very inconvenient.

Lately I tried Virtual Box again because of the Firefox problems and I reported to be very enthousiastic about it. And indeed it is a very good product. But unfortunately most of my VM's are VMware based. It is possible to run a VM in virtual box based on VMware files. But you have to create a new Virtual Box VM for that purpose that refer to the VMware files. And than you have to de-install the VMware Tools (which probably have installed in that VM) and install VirtualBox GuestAdditions. It's all doable and no rocket-science. But it's not a simple import-and-run.

But since 25th of may VMware Player 3.1 was released. And apparently Vmware released it as an answer to the Windows XP mode on Windows 7. To run older Windows XP compatible apps in Windows 7. But it occurs to me that they've looked closely to VirtualBox. The VMware Unity mode is quite comparable or actually the same as the Seamless Windows mode of VirtualBox. This is a very attractive feature that makes VMware Player as well as VirtualBox suitable to beat the Windows XP mode of Windows 7. I have not be able to try the XP mode of Windows 7. So I don't know about load times of the XP mode. But for VirtualBox and VMware Player you need to start the guest Windows to be able to use it. And you have to have an activated version of Windows in your VM.

And since VMware Player 3.1 I'm able to create VM's in Player. Actually, with being able to create VM's in Player and with the 'Shared Folder' feature I think you might say that Player is on the 'must-have'-feature-level of VMware Workstation 5.5. And since Player has a smaller foot print (100MB, about the same as Server 1.0.x) and does not need to have an Apache Tomcat running, no need for browser access of the console: VM's running in a seperate application window, Player is a very much better suitable for running VM's on a laptop/desktop. And a feature like VMware Unity/VirtualBox Seamless Windows mode is really nice. It is funny to have windows applications running in a window side by side with your Linux apps. Even copy and paste works. And having shared folders makes it possible to have your Guest-OS apps work with the same files as your host OS apps.

And what made me most lyric? I had my OpenSuse 11.1 connected to a beamer. In the NVidia conrols I had the CRT (as NVidia/X called it) placed right of my LCD desktop. Then I placed my PowerPoint in Unity on the Beamer area of the desktop (so I was able to see other apps on my lcd screen). And then it played the slideshow fullscreen on the beamer...
I was very happy about it, because I had PowerPoint 2007 working under Wine. But editing a file under PowerPoint2007/wine was not doable. Whey drag and drop or move an object on the canvas the canvas becomes black until you release the object. Only then it draws again. But in the VMware Unity mode, PowerPoint 2007 is usable under Linux!

To conclude, when to use what? A question I try to answer a lot lately.

• If you want to run VMware VM's on your own laptop along with other apps, use VMware Player
• If you want to run MS-Office 2007 or other Windows apps side by side with other applications on your Linux machine, use either VMware Player with Unity or Virtual Box with Seamless Windows mode (you may choose). But you should try if the app works properly enough under Wine, since that will give you much faster startup times and lower system-load, since you do not have to load Windows as a guest os.
• If you want to run VM's on a host that has to be reachable from different location, then use VMware Server. For example, if you have a spare desktop on the attick that you want to leverage for different purposes, then use Server. With server you can start, stop and use the VM-desktop using a browser. Unfortunatly it has to be a FireFox 3.5 at most, for the current Server version (2.x).
• If you look for an enterprise solution, look at Oracle VM or VMware ESX and their management products. These solutions are beyond my use. Since they run on 'bare-metal', and that is out of the question for me.

I don't have particular arguments for the choice between VirtualBox and VMware Player. There are other virtualization tools like KVM or Xen based. There are people that favor a particular solution over VMware because of performance. Especially the VMware would not be that fast in IO-operations. But I haven't seen any benchmarks that support this. I haven't done any measurements in particular but I did not experience any particular performance differences between VirtualBox and VMware. The only reason actually that I favor VMware is just that most of my VM's are based on VMware.

But I sincerely hope that Oracle works on improving both Oracle VM and VirtualBox in a way that get both products in line with eachother and eventually let both products work with the same VM-architecture. Then it would be able to use Oracle VM's on both Oracle VM and VirtualBox. Maybe that would be an extra stimulus to build VirtualBox/Oracle VM appliances.