SQL SERVER AWE Enabled

This option enables the use of the AWE API to support large memory sizes on 32-bit systems. With AWE enabled, SQL Server 2008 can use as much memory as the Enterprise, Developer, or Standard editions allow.

When running on Windows Server 2003 or Windows Server 2008, SQL Server reserves only a small portion of AWE-mapped memory when it starts. As additional AWE-mapped memory is required, the operating system dynamically allocates it to SQL Server. Similarly, if fewer resources are required, SQL Server can return AWE-mapped memory to the operating system for use by other processes or applications.

Use of AWE, in either Windows Server 2003 or Windows Server 2008, locks the pages in memory so that they cannot be written to the paging file. Windows has to swap out other applications if additional physical memory is needed, so the performance of those applications might suffer. You should therefore set a value for Max Server Memory when you have also enabled AWE.

If you are running multiple instances of SQL Server on the same computer, and each instance uses AWE-mapped memory, you should ensure that the instances perform as expected. Each instance should have a Min Server Memory setting. Because AWE-mapped memory cannot be swapped out to the page fi le, the sum of the Min Server Memory values for all instances should be less than the total physical memory on the computer.

If your SQL Server is set up for failover clustering and is configured to use AWE memory, you must ensure that the sum of the Max Server Memory settings for all the instances is less than the least physical memory available on any of the servers in the cluster. If the failover node has less physical memory than the original node, the instances of SQL Server may fail to start.

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