Server consolidation and disaster recovery planning

Server consolidation has been the talk of IT departments for several years, and represents a still popular cost cutting move. The concept is simple: rather than dedicate applications to individual servers, which can result in underutilized servers, install multiple applications onto servers in order to more efficiently utilize server hardware, thereby reducing costs.

I’m all for saving money, electricity, natural resources, and so on, and consolidating servers is a smart move to undertake, as long as you abide by this principle:

Server consolidation is something to undertake during peacetime, not solely for recovery purposes.

Let me expand on this. Consider an environment that is made up of dozens of underutilized servers dedicated to applications. The DR planning team wants to consider a DR strategy that consolidates these applications onto fewer servers as a way of providing a lower-cost recovery capability.

Well, it might work, but I’d want to test it very thoroughly and carefully. Combining applications that are used to having servers all to themselves may lead to unexpected interactions that could be difficult to troubleshoot and untangle.

If you want to undertake server consolidation, do it first in your production environment, and then take that consolidated architecture and apply it to a DR architecture.

– from IT Disaster Recovery Planning for Dummies