SQL Server 2008 introduced a new feature, Management Data Warehouse (MDW), which allows users to collect metrics on their servers over time to aid in performance troubleshooting. A lot of people try this feature out, because it is easy to set up, and then find that it is not so easy to remove. In fact, removing MDW is not supported; in SQL Server 2012, though, a new system stored procedure was added to make this process easier. The problem is that this stored procedure (as well as several of the workarounds I've seen published) can leave several objects behind.
This article presents a case study of using the Management Data Warehouse feature in SQL Server 2008 to analyze disk usage trends by product.