Recently, I’ve had to distribute a large VMware virtual machine. The VMware image, uncompressed, as it sits on my hard disk is 21.3 GB in size.  I compressed the image with WinZip, RAR and 7zip in order to determine which was the most efficient compression algorythm (at least for this one VM).  Here are my results:

  • Uncompressed Size: 21.3 GB
  • Winzip: 10.5 GB
  • WinRAR: 9.7 GB
  • 7Zip: 8.8 GB

For WinZip, I chose bzip2 compression, or Maximum compression as it is know in earlier versions of WinZip.  For RAR, I chose “Good”, and for 7Zip I chose “Maximum”.  For all three, there are many compression options, and I chose, as a general rule, the 2nd most compact.  The more compact, the more time it takes to compress.   Hope this helps you decide which tool to use to compress your VM images.