The VM was allowed to dominate the entire server simply because...it was a test server. The point of the testing is to see if/how patches and updates change the behaviour profile of an application. If the behaviour profile of an application changes, then the entire virtual instance changes and I then go back and recalculate my load balancing.
Virtualisation is a tool in a systems administrator’s arsenal, no different from any other. While resource constraints are a fine thing in a production environment, they make absolutely no sense to me in a testbed environment. I view my testbed virtual servers similarly to how I view calibrating my various test equipment: it is there to provide you with baselines against which you can measure issues in production.
Given the radical nature of the performance changes delivered by this patch, I would say that this application server is quite simply no longer a candidate for virtualisation. Put another way: my calibration tests determined that the tool I was using is no longer valid for the environment in which it must operate. Indeed, this incident makes me grateful that I /don’t/ run my testbed systems with resource constraints. With resource constraints in place I may never have caught this performance difference. Had I not caught it, we would not be able to take advantage of the vastly superior report generation times this patch enables.
More to the point…it allows us to simply remove from service several instances of Windows Server we had been using to run “report servers” in order to compensate for the slow report generation features of this application. This frees up licences that I can use elsewhere for other projects. All in all, win/win/win largely because I take the time to reprofile my applications with every patch by running them on an “unlocked” server.
Based upon the performance delta, I have already begun the process of sourcing equipment to properly physicalise this server. This patch will not be applied to the production environment until that production environment has been fully physicalised.