Virtualization pitfall warning

You don't have to read my blogs for long to know that I'm really keen on virtualization, so I was fascinated by this story on potential pitfalls: Experts Warn of Virtualization.

I say fascinated not because I think it's wrong - I think it's completely right. Virtualization has lots of benefits - better hardware utilization is the main one, lower running costs is another, and all this is usually coupled with easier and more centralized management - but it isn't a cure all for all processes and environments, and if done badly, creates more problems than it solves.

Also, as the article points out, when using virtualization you can end up simplifying your hardware structure, without actually simplifying, and in some cases exacerbating your management worries by increasing the number of machines you need to manage.

If you are going to use virtualization, use it to condense your server requirements in a consolidation exercise, rather than trying to virtualize everything. If you have 60 hardware servers and determine you can virtualize to just 15 with 4 VMs per hardware unit, then get rid of the 45 servers you just demoted.

If you are using virtualization as a method for separation (for example, providing separate file, email or other servers for individual departments), try to be as coarse as possible. Going too far down the separation route can increase your administration costs and add to the complexity of your site. Conversely, too few may not result in proper separation, and in the case of a combined consolidation/separation project, may not actually save you any time in the process.