A resource pool, or pool, represents the physical resources of the server. You can think of a pool as a virtual SQL Server instance inside of a SQL Server instance. A pool has two parts. One part does not overlap with other pools, which enables minimum resource reservation. The other part is shared with other pools, which supports maximum possible resource consumption. In this release of Resource Governor the pool resources are set by specifying one of the following for each resource: MIN, MAX or CAP for CPU MIN or MAX for memory MIN and MAX represent the minimum guaranteed resource availability of the pool and the maximum size of the pool, respectively, for each of these resources. The CAP value for CPU represents a hard maximum. Available CPU capacity above this value will not be used. The sum of MIN values across all pools cannot exceed 100 percent of the server resources. MAX and CAP values can be set anywhere in the range between MIN and 100 percent inclusive. If a pool has a nonzero MIN defined, the effective MAX value of other pools is readjusted. The minimum of the configured MAX value of a pool and the sum of the MIN values of other pools is subtracted from 100 percent. The following table illustrates the preceding concepts. The table shows the settings for the internal pool, the default pool, and two user-defined pools. The following formulas are used for calculating the effective MAX% and the shared %. Min(X,Y) means the smaller value of X and Y. Sum(X) means the sum of value X across all pools. Total shared % = 100 - sum(MIN %). Effective MAX % = min(X,Y). Shared % = Effective MAX % - MIN %. Using the preceding table as an example we can further illustrate the adjustments that take place when another pool is created. This pool is Pool 3 and has a MIN % setting of 5.
