If you're planning a virtual desktop infrastructure (VDI) environment, then virtualizing your servers as an alternative is perhaps not the most obvious thing in the world to do. But then the benefits of server virtualization are not always the obvious ones -- as we'll shortly see.
Here's the story: Dutch mental health center Riagg Rijnmond was using a Citrix-based virtual desktop system to provide 350 employees with access to Microsoft Office and various other applications, many of which are actually web based. Trouble was, the system was five or six years old and needed to be upgraded. That was going to be expensive, especially when the license costs for Windows Server, client access licenses and all the rest of the required software was factored in.
The organization decided to switch to an open source-based solution using Xubuntu desktops, OpenOffice productivity software and sever-based computing software called NX Server from Italy-based NoMachine. This enabled Riagg Rijnmond to reduce its desktop budget by two-thirds.
The interesting thing about this implementation -- which was carried out by NoMachine's Dutch partner, ECsys -- is that it makes use of good old-fashioned server-based computing. For all the talk of VDI heard from desktop virtualization vendors, server-based computing is still alive and well, delivering the benefits of centralized administration and data storage.
But here's the twist: NoMachine is quite capable of providing desktop access to 100 to 150 users per server, but what happens if one these NoMachine servers goes down? That would be a problem, as you can't swiftly move 150 users to another server; there simply wouldn't be the capacity to run the additional load, said Nieck Zanen, ECsys's president. "For that reason, Riagg Rijnmond decided that it didn't want any more than 25 users on a single terminal server," he said
You could buy lots of servers and just put 25 or so on each one, so if a NoMachine server goes down you have to find homes for only 25 users on other servers. That would work, but it's hardly an efficient use of server resources.
So what ECsys ended up doing for Riagg Rijnmond was to make use of server virtualization technology to enable its server-based desktops work more like VDI. If this sounds like a convoluted way of doing things, then that's because it is, but in this case it worked rather well.
ECsys used the Xen hypervisor (naturally, this is an open source story, after all) to virtualize the NoMachine servers to provide user access to the desktops, with about 25 users per virtual machine. It then ran four or five of these virtual machines on each physical server. Now, if a NoMachine server goes down, only 25 staff members lose desktop access until they can be moved to another server.
True desktop virtualization is still developing, and the "war" -- such as it is -- between VDI and SBC is perhaps a phony one. But by using open source software and adding a dose of server virtualization, ECsys has shown that there is plenty of life left in the old SBC dog yet.
The moral of the story? Server virtualization technology is widely used and widely useful. VDI? As yet, not so much
Paul Rubens is a journalist based in Marlow on Thames, England. He has been programming, tinkering and generally sitting in front of computer screens since his first encounter with a DEC PDP-11 in 1979.