The Resource Governor relies on resource pools, workload groups, and classifier functions. This section covers these concepts. You need to understand them before using the Resource Governor.
A resource pool collects physical resources together so that you can manage them. Under the covers, a resource pool acts as a virtual instance of SQL Server when accessed by an application. It has a number of parameters including the minimum and maximum values for the resource. This may include CPU utilization and memory usage. (File I/O is planned for a later version of SQL Server — most DBAs currently reduce I/O contention by separating databases, tables, or indexes onto different physical disks.) SQL Server 2012 can have up to 64 user-defined resource pools (64-bit versions only), up from the limit of 18 in the previous release. In addition, there are two built-in pools:
SQL Server DBAs can also define their custom resource pools. The custom resource pools can define limits for each resource with minimum and maximum values. The sum of all resource pool minimum values can't exceed 100 percent. The maximum values for each resource pool can range from 0 to 100.
A resource pool cannot always operate at its maximum value. The reason ...