XADM: Exchange Server Unavailable at Regular Intervals, PerfMon Shows Spike

ID: Q247775

The information in this article applies to:

Microsoft Exchange Server, version 5.5

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SYMPTOMS

When you are administering Microsoft Exchange Server 5.5, you may receive reports every six hours that users are unable to gain access to their inboxes. This lasts for about 15 minutes and occurs on an Exchange Server that has many more inboxes than the other servers in the site.

When you examine the MSExchangeDS\Pending Replication Synchronization counter in Performance Monitor, you see that the counter records abnormally high numbers during the problem time periods.

CAUSE

This behavior can occur when the server's Directory service is unable to handle all of the remote procedure call (RPC) requests it receives.

RESOLUTION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

To resolve this issue, change two values in the registry. Follow these steps:

Start Registry Editor (Regedt32.exe).

Locate the Max Threads(EXDS+NSP+DSA) value entry under the following registry key:


HKLM\System\CurrentControlSet\Services\MSExchangeDS\Parameters

Double-click the value and set it to the equivalent of (50 * number of processors) + 30.

Locate the Replicator Maximum concurrent read threads value entry under the following registry key:


HKLM\System\CurrentControlSet\Services\MSExchangeDS\Parameters

Double-click the value, and then set it to zero (0).

Quit Registry Editor.

MORE INFORMATION

When you examine the Period-Rep-Sync-Times attribute on the site properties dialog box in Raw mode, you see that the schedule is set at every six hours. This is the interval at which each server in the site sends out requests to get Directory updates from within the site.

Additional query words:

Keywords :
Version : winnt:5.5
Platform : winnt
Issue type : kbprb