correct-affinity-mask-and-affinity-input-and-output-mask-overlap.md

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Correct affinity mask & affinity IO mask overlap policy	Learn how to enable a policy that checks whether an instance of SQL Server has one ore more processors that are assigned to be used with both the affinity mask and the affinity I/O mask options for Policy-Based Management in SQL Server.	VanMSFT	vanto	12/15/2023	sql	security	reference	Best Practices [Database Engine]

Correct affinity mask and affinity input and output mask overlap

[!INCLUDE SQL Server] This rule checks whether the instance of [!INCLUDEssNoVersion] has one or more processors that are assigned to be used with both the affinity mask and the affinity I/O mask options. On a computer that has more than one processor, the affinity mask and the affinity I/O mask options are used to designate which CPUs are used by [!INCLUDEssNoVersion]. Enabling a CPU with both the affinity mask and the affinity I/O mask can slow performance by forcing the processor to be overused.

Best practices recommendations

When you specify either the affinity mask or the affinity I/O mask options, you should specify both, but only enable each CPU no more than once.

Don't enable the same CPU in both the affinity mask option and the affinity I/O mask option. The bits that correspond to each CPU should be in one of the following states:

• 0 in both the affinity mask option and the affinity I/O mask option

• 0 in the affinity mask option and 1 in the affinity I/O mask option

• 1 in the affinity mask option and 0 in the affinity I/O mask option

For more information

affinity mask Server Configuration Option

affinity Input-Output mask Server Configuration Option

affinity64 mask Server Configuration Option

affinity64 Input-Output mask Server Configuration Option

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