XADM: An Exchange 2000 Server with the "/3GB" Switch in the Boot.ini File May Lose Network Connectivity Under a Heavy Messaging Load (313707)
The information in this article applies to:
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Datacenter Server
- Microsoft Exchange 2000 Server
- Microsoft Exchange 2000 Enterprise Server
This article was previously published under Q313707 IMPORTANT: This article contains information about modifying the registry.
Before you modify the registry, make sure to back it up and make sure that you
understand how to restore the registry if a problem occurs. For information
about how to back up, restore, and edit the registry, click the following
article number to view the article in the Microsoft Knowledge Base: 256986 Description of the Microsoft Windows Registry
SYMPTOMS If Exchange 2000 Server is running on a Windows 2000
Advanced Server-based computer or a Windows 2000 Datacenter Server-based
computer with the /3GB switch in place (in the Boot.ini file), the computer may lose
network connectivity (especially when messaging traffic is high). You may have
to restart the server to restore network connectivity.
CAUSE This problem may occur if the kernel uses up the Free
System page table entries (PTEs) on heavily loaded servers that are configured
with the /3GB switch. This results in random network problems (the server drops
packets or can no longer be pinged), which may require a system restart.
RESOLUTION To resolve this problem, you can modify the SystemPages registry value to increase the PTE pool; however, modify the SystemPages value only if you determine that the server is in a low PTE
state. To determine if the server is in a low PTE state, use the following
system monitor counter to track Free System PTEs:
Performance Object: Memory
Counter: Free System page table entries
This counter is used to monitor the available PTEs on the server.
Typically, an Exchange 2000 server with the /3GB switch set should show 10,000 or more free PTEs during heavy
messaging stress. If this counter dips below 10,000 and you experience network
problems, you can modify the SystemPages registry value to resolve the low PTE
condition. WARNING: If you use Registry Editor incorrectly, you may cause serious
problems that may require you to reinstall your operating system. Microsoft
cannot guarantee that you can solve problems that result from using Registry
Editor incorrectly. Use Registry Editor at your own
risk. To modify the SystemPages value:
- Start Registry Editor (Regedt32.exe).
- Locate and double-click the SystemPages value under the following key in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management - Delete the existing value, click Decimal, type 30000,
and then click OK.
Important Windows 2000 Service Pack 3 (SP3) with the /3GB switch increased available Paged Pool memory to 258 megabytes (MB) at the
expense of PTEs. Only 16,384 PTEs are available when you use the /3GB switch, so set the SystemPages value to 30000 to start with a greater number of PTEs. You can adjust this number up or down, depending on the available PTEs and the available paged pool memory. - Quit Registry Editor.
If you set this key to 30000, you increase the PTE pool by 30
MB. This 30 MB is taken from the Paged Pool Memory space. In other
words, if you increase your PTE pool by 30 MB, you reduce the Paged Pool Memory
by 30 MB. Reducing Paged Pool Memory may adversely affect the computer's
performance, so modify the System Pages registry value only if you must. STATUSMicrosoft has confirmed that
this is a problem in Microsoft Exchange 2000 Server.
| Modification Type: | Minor | Last Reviewed: | 4/28/2005 |
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| Keywords: | kbfix kbprb KB313707 |
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