Thursday, September 25, 2008

PageFile Size Larger Than Total Physical Memory

PageFile Size Larger Than Total Physical Memory
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: 2008-01-03

The Microsoft Exchange Analyzer Tool 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 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.

If the Exchange Analyzer determines that the value for the Win32_PageFile MaximumSize key is larger than 1.05 times the value of the Win32_ComputerSystem TotalPhysicalMemory key, an error is displayed.

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.

The recommended page file size is equivalent to 1.05 times the RAM up to a maximum of 4,095 MB. This means that the largest paging file size per volume that you can set is 4,095 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.

For more information about page files, see the following Microsoft Knowledge Base articles:

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