Now, let’s “peel the onion” a little more into the core architecture of SQL Server itself. Figure 38.2 shows the primary components within a SQL Server instance. The major issues to worry about at the instance level are the caches that comprise the memory pool and the number of CPUs available for processing to SQL Server itself (shown as white boxes, not dark ones). Of course, the disk I/O subsystem and files have to be carefully evaluated and used effectively as well. All other grayed-out boxed items such as the SQL Server kernel are not within your control.