Microsoft KB Archive/312362

= Server is unable to allocate memory from the system paged pool =

Article ID: 312362

Article Last Modified on 2/28/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows 2000 Service Pack 2
 * Microsoft Windows 2000 Service Pack 3
 * Microsoft Windows 2000 Service Pack 4
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Service Pack 3

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This article was previously published under Q312362



Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
When your server is under a heavy load, the Server service may repeatedly log the following error (in the System Event log) that indicates that the server is out of paged pool memory:

Source - SRV

Type - Error

Event ID - 2020

Description -

The server was unable to allocate from the system paged pool because the pool was empty.

Data -

0000: 00040000 00540001 00000000 c00007e4

0010: 00000000 c000009a 00000000 00000000

0020: 00000000 00000000 0000000b



CAUSE
Several factors may deplete the supply of paged pool memory. Enabling pool tagging and taking poolsnaps at different time intervals may help you to understand which driver is consuming paged pool memory. If the poolsnaps indicate that the MmSt tag (Mm section object prototype PTEs) is the largest consumer and paged pool memory has been depleted or the system is logging error event 2020s, there is a large probability that there are a very large number of files that are open on the server. By default, the Memory Manager tries to trim allocated paged pool memory when the system reaches 80 percent of the total paged pool. Depending on the system configuration, a possible maximum paged pool memory on a computer can be 343MB and 80 percent of this number is 274MB. If the Memory Manager is unable to trim fast enough to keep up with the demand, the event that is listed in the &quot;Symptoms&quot; section of this article may occur. By tuning the Memory Manager to start the trimming process earlier (for example, when it reaches 60 percent), it would be possible to keep up with the paged pool demand during sudden peak usage, and avoid running out of paged pool memory.



RESOLUTION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

The following tuning recommendation has been helpful in alleviating the problem:  Start Registry Editor (Regedt32.exe). Locate and then click the following key in the registry:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Memory Management

 On the Edit menu, click Add Value, and then add the following registry value:

Value name: PoolUsageMaximum

Data type: REG_DWORD

Radix: Decimal

Value data: 60

Setting the value at 60 informs the Memory Manager to start the trimming process at 60 percent of PagedPoolMax rather than the default setting of 80 percent. If a threshold of 60 percent is not enough to handle spikes in activity, reduce this setting to 50 percent or 40 percent.

Value name: PagedPoolSize

Data type: REG_DWORD

Radix: Hex

Value data: 0xFFFFFFFF

Setting PagedPoolSize to 0xFFFFFFFF allocates the maximum paged pool in lieu of other resources to the computer. Quit Registry Editor. Restart the server for the changes to take effect.</ol>

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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.

Keywords: kberrmsg kbenv kbprb KB312362

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