Page File Size is Less than Physical Memory Size Plus 10 MB

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2010-04-28

The Microsoft Exchange Best Practices Analyzer queries the Active Directory directory service to determine the value of the serialNumber attribute for all objects that have an object class of msExchExchangeServer. The following table contains a key to the attribute values.

Value contains The computer is running

Version 5.5

Microsoft Exchange Server 5.5

Version 6.0

Microsoft Exchange 2000 Server

Version 6.5

Microsoft Exchange Server 2003

Version 8

Microsoft Exchange Server 2007

Version 14

Microsoft Exchange Server 2010

The Exchange Analyzer also queries the Win32_PageFile Windows® Management Instrumentation (WMI) class to determine the value for the MaximumSize key. This key represents the current configured maximum page file size.

The page file (pagefile.sys) is a hidden file on the hard disk that is used by Windows to retain temporary data when the system is running low on RAM. The page file is also known as paging file or swap file. Virtual memory consists of page file and RAM.

Finally, the Exchange Analyzer also queries the Win32_ComputerSystem WMI class to determine the value set for the TotalPhysicalMemory key. This value represents the amount of RAM installed on the computer.


Be aware that, under some circumstances, the TotalPhysicalMemory property may not return an accurate value for the physical memory. For example, it is not accurate if the BIOS is using some of the physical memory.

If the Exchange Analyzer determines that the value for the Win32_PageFile MaximumSize key is less than the value of the Win32_ComputerSystem TotalPhysicalMemory key plus 10 MB, a warning is displayed.

As documented in the Exchange 2007 System Requirements and Exchange 2010 System Requirements, the recommended paging file size is equal to the amount of RAM in the server plus 10 MB.

This paging file size recommendation accounts for the amount of memory needed to collect information if the operating system fails. By default, if the operating system fails, it will copy everything in memory to a .dmp file. That file can be examined later to determine the cause of the failure. To be able to copy everything that is stored in memory, you must have a paging file size that can hold everything in memory, plus some additional space to gather the data.

To address this warning, increase the paging file size to equal the amount of RAM in the server plus 10 MB.


To prevent page file fragmentation, we recommend that you set the paging file size initial and maximum values to be the same value. If you reduce the size of either the initial or maximum page file settings, you must restart your computer to see the effects of those changes. Increases typically do not require a restart.

To change the page file settings

  1. Click Start, Control Panel, and then click System.

  2. On the Advanced tab, under Performance, click Settings.

  3. In the Performance Options dialog box, on the Advanced tab, under Virtual Memory, click Change.

  4. Under Drive [Volume Label], click the drive that contains the paging file that you want to change.

  5. Under Paging file size for selected drive, click Custom size, and enter the recommended page file size in megabytes in the Initial size (MB) and Maximum size (MB) fields, and then click Set.