What is IO affinity?

We 2 type of affinity CPU affinity and IO affinity these two affinities’s collectively called as processor affinity.

If you have multiple CPU running in single machine and reading data from disks. If IO operation performance is good then SQL Server performance also will be good. We can assign resource to CPU affinity and IO affinity.

Go SQL Server Instance right click à go to Properties à Processor you will see below options

1      Automatically set processor affinity mask for all processors

2     Automatically set I/O affinity mask for all processors

By selecting these options you can see all CPU available. So now you can select which CPU’s which you want  use for I/O affinity.