Virtual Machines
Recently I’ve had a change of heart concerning virtual machines in business environments. There has been a lot of hype about consolidating multiple existing physical servers into a single physical server hosting each of the virtual servers. It’s been promoted as low-cost and energy-efficient, but this approach ignores the fact that all of the consolidated servers now depend on the same physical hardware – known as a ’single point of failure.’
It wouldn’t be the end of the world if your DHCP server went down for a few hours because of a bad system board, but what happens when your DNS, DHCP, File, Print, and application servers all go down at the same time? Is that risk worth the money you saved on server hardware? While you can find combinations that work well, this kind of transition must be carefully planned out, and many small business networks may not benefit from consolidating their servers.
Before, I would have universally discouraged virtual servers in very small networks, but I’ve found some very good uses for them over the past few months. Mosso and Slicehost, sister companies owned by Rackspace, offer low-cost Virtual Private Servers (VPS) at a usage-based rate. They allow you to rent part of a server for much less than it would cost you to have your own. They also let you set up automatic daily and weekly backups.
With this kind of VPS, I can set up a directory server (for example) for about $12 a month. This is a huge savings over buying the hardware myself, and I get a dedicated IP address and automated backups. There is no longer a single point of failure because my virtual servers are not hosted on the same physical server. Even in the event that there is a hardware failure, I know that a VPS provider has techs who can respond immediately, and very likely they have spare parts available for that model.
Another big plus about using a hosted VPS is that your server is available from anywhere. You don’t have to worry about creating a DMZ in your network that internet computers can access, and you don’t have to worry about updating a dynamic DNS entry. While you do have to make sure your server is secured, you can now reach it from your netbook at a wifi hotspot.
A few days ago, I had a need to set up a new Windows XP client to do some testing in Internet Explorer. Rather than spend an hour installing Windows on a physical computer, I used VirtualBox to create a new Virtual Machine on my Ubuntu computer. I booted the VM from an ISO image of the Windows XP SP3 OEM disc, and had Windows installed and running in very little time without even having to leave my desk.
So overall, I think there are some great ways virtual machines can save you time and money, but they still aren’t necessarily the right answer every time.
