VirtualBox is a family of powerful x86 virtualization products for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers, it is also the only professional solution that is freely available as Open Source Software under the terms of the GNU General Public License (GPL).
I really like new Opensource VirtualBox from Sun. It is light on resources. Quick tip on you can convert a VMware virtual machine to a VirtualBox machine using qemu-img utility.
*Note:- Before Converting make a backup copy of your vmware image
qemu-img is included with qemu package. You can install it by typing:
$ sudo apt-get install qemu
$ yum install qemu
Convert a VMWare Image to VirtualBox Image
Convert VMWare image called freebsd.vmdk to /tmp/freebsd.bin
$ qemu-img convert freebsd.vmdk /tmp/freebsd.bin
Now use VBoxManage to get back image in native format:
$ VBoxManage convertdd /tmp/freebsd.bin freebsd.vdi
VirtualBox can run VMs created by VMware Workstation or Server for this you need to import vmdk files using the following procedure
* Start Virtual Box
* Goto File > Virtual Disk Manager
* Click Add. Locate and select the copied .vmdk file. Click OK.
* Create a New VM as usual using the added vmdk file
* Boot the VM