Topic Last Modified: 2006-03-16

The Microsoft® Exchange Server Analyzer Tool queries the Win32_PerfRawData_PerfOS_Memory Microsoft Windows® Management Instrumentation (WMI) class to determine the current value for the PoolPagedBytes key. The actions taken by the Exchange Server Analyzer depends on the underlying operating system, the presence or absence of the /3GB switch in the Windows Boot.ini file, and the discovered value for this key.

The table displays the matrix of evaluations used by the Exchange Server Analyzer to determine whether this value is out-of-bounds for a given Exchange server. If the conditions in the table are matched, a warning is displayed.

Operating system	Boot.ini setting	Current paged pool is
Windows 2000 Server or Advanced Server	/3GB	180 MB or more
Windows 2000 Server or Advanced Server	None	180 MB or more
Windows Server™ 2003	/3GB	200 MB or more
Windows Server 2003	None	300 MB or more

The PoolPagedBytes key value is the size, in bytes, of the kernel memory paged pool. The paged pool is an area of physical system memory for objects that can be written to disk when they are not being used. This value for this key is the last observed value. On a healthy Exchange server, unless a backup or restore is taking place, there should be no more than 180 MB of paged pool memory being used.

In Windows 2000 Server and Windows 2000 Advanced Server, the maximum value for paged pool memory is 470 MB. When the /3GB switch is added to a computer running Windows 2000 Advanced Server, the maximum value for paged pool memory is 192 MB. On a computer running Windows Server 2003 without the /3GB switch, the maximum value for paged pool memory is 491 MB. On a computer running Windows Server 2003 with the /3GB switch, the maximum value for paged pool memory is 256 MB.

Because there is no way to increase the limit for paged pool memory beyond the values listed above, this condition should be corrected as soon as possible. Regardless of the operating system in use or the presence or absence of the /3GB switch, only so much paged pool memory can be accessed by Windows. If Windows runs out of kernel memory, it can display error messages and crash. Kernel memory is essential to the proper operation of the system, and therefore you should monitor kernel memory carefully.

If, after restarting the Exchange server, this condition recurs, the next step is to ensure that your system is tuned properly and that all of the software and hardware on this system is up to date. This includes installing the latest:

• Windows operating system service pack
  
  
• Exchange Server service pack
  
  
• Hardware firmware and drivers
  
  
• System BIOS updates
  
  
• Updates for any third-party applications that are installed and running
  
  

If software and hardware updates do not resolve this problem, you should disable all third-party software, restart the Exchange Server computer and monitor kernel memory.

To correct this warning

For more information about tuning Exchange Server properly, see the following Microsoft Knowledge Base articles and Exchange topic:

• 815372, "How to Optimize Memory Usage in Exchange Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=815372)
  
  
• 266096, "XGEN: Exchange 2000 Requires /3GB Switch with More Than 1 Gigabyte of Physical RAM" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=266096)
  
  
• "Troubleshooting Exchange Server 2003 Performance" (http://go.microsoft.com/fwlink/?LinkId=47588)
  
  
• "Troubleshooting Exchange 2000 Server Performance" (http://go.microsoft.com/fwlink/?LinkId=18177)
  
  
• "Exchange Server 2003 Performance and Scalability Guide" (http://go.microsoft.com/fwlink/?LinkId=47576)
  
  

For more information, see the following Exchange blog articles:

• "Microsoft Windows Kernel Memory Management and Microsoft Exchange Server" (http://go.microsoft.com/fwlink/?LinkId=63477)
  
  
• "Configuring Hot-Add and Large Memory for Exchange 2003" (http://go.microsoft.com/fwlink/?LinkId=63478)
  
  
• "Large Security Tokens and Kernel Memory Exhaustion" (http://go.microsoft.com/fwlink/?LinkId=63479)
  
  

  Note:
  The links to these blogs are provided for informational purposes. The content may change without notice.

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