Improve Virtual Memory
Topic Last Modified: 2005-11-18
The Microsoft® Exchange Server Analyzer Tool has determined that your server as virtual memory fragmentation issues.
In 32-bit Microsoft Windows® systems, there are two kinds of memory:
- Physical memory Amount of actual memory installed in the system
- Virtual memory address space A virtualized 4-GB memory space
Regardless of how much physical memory is installed on the system, the total size of the virtual address space is always the same: 4 GB. Although it is not the case for all 32-bit applications, in the case of Exchange Server, virtual address space equals virtual memory. The terms are used interchangeably.
During the normal course of its operations, the Exchange store will repeatedly allocate, use, and de-allocate virtual memory. When virtual memory is allocated, used, and de-allocated frequently, virtual memory fragmentation can result. Virtual memory fragmentation is analogous to file system fragmentation that can occur over time. After a while, allocated segments of virtual memory are no longer contiguous, and performance begins to suffer. In the case of the file system, you can run an application that performs defragmentation of the file system. In most cases, defragmentation can be done while the system is online and being accessed. In the case of virtual memory fragmentation, there is no defragmentation tool. Instead, to correct the problem, you must stop and start the Microsoft Exchange Information Store service or reboot the system.
Virtual memory fragmentation can be caused by third-party software running in the store/inetinfo processes. Make sure you have the latest drivers for any third-party applications. If the problem is reproduced after restarting, consider disabling third-party software or moving user mailboxes to another server to reduce server load and see if the problem stops. For more information, see Move User Mailboxes to Another Server.
For more information about Exchange Server performance, see the Exchange Server 2003 Performance and Scalability Guide (http://go.microsoft.com/fwlink/?LinkId=47576).
For more information about troubleshooting Exchange Server performance issues, see Troubleshooting Microsoft Exchange Server 2003 Performance (http://go.microsoft.com/fwlink/?LinkId=47588).
For more information about troubleshooting virtual memory fragmentation in Microsoft Exchange Server 2003 and Exchange 2000 Server, see Microsoft Knowledge Base article 325044, "How to troubleshoot virtual memory fragmentation in Exchange Server 2003 and Exchange 2000 Server" (http://go.microsoft.com/fwlink/?LinkId=3052&kbid=325044).
For more information about how to optimize virtual memory usage, see Knowledge Base article 815372, "How to optimize memory usage in Exchange Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=815372).
For more information about moving user mailboxes to reduce server load, see Move User Mailboxes to Another Server.