Resource and Memory Management Technologies

Updated: March 28, 2003

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Resource and Memory Management Components

4GT and PAE X86 are available only in the 32-bit editions of Microsoft Windows Server 2003, Enterprise Edition, or Microsoft Windows Server 2003, Datacenter Edition, of the Windows Server 2003 family. Both technologies can provide user applications with access to additional RAM. The default virtual address space and flat addressing used on the 64-bit versions of these products negates the need to use these technologies on the 64-bit platforms.

4GT makes more of the computer’s virtual memory available to applications by making less virtual memory available to the operating system. 4GT allows applications to address 3 gigabytes (GB) of virtual memory instead of the 2 GB normally allocated for user mode processes. This is a 50 percent increase in virtual memory for the applications, allowing more data to be cached by the application, which can significantly increase performance.

PAE X86 provides the operating system access to memory beyond the default memory address limit of 4 GB. PAE X86 allows software that uses the Address Windowing Extensions (AWE) API set and runs on computers with more than 4 GB of physical memory to map additional physical memory into the application’s virtual address space. Applications not using the AWE API set can also benefit from PAE X86 because the operating system uses the larger physical memory to reduce paging and thus increase performance.

Windows System Resource Manager (WSRM) is a tool used to programmatically manage server resources such as processor utilization and memory allocation. Using policies, Windows System Resource Manager allocates specific amounts of resources to applications or processes. These policies allow system administrators to set usage limits based on a percentage of available CPU resources as well as set affinities between managed applications and certain CPUs in the case of multi-processor servers. Windows System Resource Manager consists of two components: the service and the client. The service component can be installed only on the 32-bit and 64-bit versions of Windows Server 2003, Enterprise Edition, and Windows Server 2003, Datacenter Edition. The client component can be installed only on 32-bit versions of the Windows Server 2003 family. The client component does not support the 64-bit versions of these operating systems.

Resource and Memory Management Scenarios

The resource and memory management technologies described in this collection are typically used in server consolidation scenarios and other enterprise systems that make use of large servers with large amounts of memory and multiple CPUs.

4GT is most commonly used when servers are hosting memory intensive applications, such as database management systems, whose performance is directly affected by the availability of physical memory. Servers can take advantage of 4GT provided they have at least 2 GB of RAM available.

PAE X86 is used on servers with more than 4 GB of physical memory. PAE X86 allows the Windows executive software (also known as the kernel) to take full advantage of all available physical memory, including memory above 4 GB, up to 64 GB. Certain data-intensive applications, such as database management systems and scientific and engineering software that need access to very large caches of data, can use the Application Windowing Extensions (AWE) API set to access the memory that PAE can provide beyond 4 GB.

Windows System Resource Manager is most effective on systems where the CPU is in high demand. In these situations, Windows System Resource Manager manages competing processes by raising and lowering process priority. Windows System Resource Manager also provides a mechanism to store and retrieve records of the behavior of managed processes. With this information, Windows System Resource Manager can be used to generate reports of process-resource usage on a per-user, per-application, or other relevant basis. This accounting data can also be used to provide charge-back accounting.

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