With the introduction of SQL Server 2005, Microsoft introduced Dynamic Management Views (DMVs) which allow you to get better insight into what is happening in SQL Server. Without these new tools a lot of the information was unavailable or very difficult to obtain.
DMVs are a great tool to help troubleshoot performance related issues and once you understand their power they will become a staple for your Database Administration.
The DMVs were introduced in SQL 2005 and with each new release, Microsoft has been adding additional DMVs to help troubleshoot issues. DMVs actually come in two flavors DMVs (dynamic management views) and DMFs (dynamic management functions) and are sometimes classified as DMOs (dynamic management objects). The DMVs act just like any other view where you can select data from them and the DMFs require values to be passed to the function just like any other function.
The DMVs are broken down into the following categories:
Here are some of the more useful DMVs that you should familiarize yourself with:
Here are some additional articles about DMVs.