The CVS, or Concurrent Versioning System is an open source application applied to the VPS server web site. It allows several developers to work together, even from many different locations, on any software project. It saves all changes in a set of files and keeps track of all work done, updating continuously. It was created as an update to normal Version Control Systems, or VCS. The CVS is generally compatable with all types of servers, although there are exceptions, depending upon the hosting program being used.

An SVN is a Subversion program, and is only able to be used with a dedicated server or a VPS. It requires access to the root files and folders and is considered to be a mostly compatable upgrade to a CVS application. The two can be used together, if there is the need for them both to be functional to maximize the website’s potential. With multiple developers each program has it’s merits on their own, and combined can truly be a great set of assets to any site.
http://myhosting.com/blog/2011/01/svncvs-vps-server-2/