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Exchange Server experiences performance issues when a PDC emulator is used for DSAccess or ADAcess
Article ID: 298879 - View products that this article applies to.
This article was previously published under Q298879
By default, DSAccess or ADAccess chooses the primary domain controller (PDC) emulator operations master role computer to handle requests in Microsoft Exchange. This action may result in poor performance if other non-Exchange programs are making heavy use of the PDC emulator.
To resolve this issue, use one of the following methods, as appropriate for your situation.
Method 1: Microsoft Exchange 2000 Server and later versions
To resolve this problem in Exchange 2000 Server and later versions, add the MinUserDC registry value to exclude the PDC emulator from the server list that Exchange can use.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
To add the MinUserDC registry value, follow these steps:
In Exchange Server 2007 and in Exchange Server 2010, you can use a cmdlet to configure the ADAccess component to exclude a particular domain controller or a list of domain controllers from use. To do this, use the Set-ExchangeServer command together with the StaticExcludedDomainControllers option.
The following example shows how to use the Set-ExchangeServer command to exclude one or more domain controllers from use. Additionally, this example shows how to verify the status of the Exchange environment after you run the Set-ExchangeServer command.
In this example, you have the following servers:
To use the Set-ExchangeServer command to exclude the three domain controllers that are listed in this table from use for the DSAccess component, follow these steps:
Collapse this tableExpand this table
Set-ExchangeServer -identity E2K7-1.contoso.com -StaticExcludedDomainControllers:$null
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
In Exchange Server 2007 and in Exchange Server 2010, you can use the Set-ExchangeServer cmdlet to configure the ADAccess component to exclude a particular domain controller or a list of domain controllers from use. You do not have to edit the registry when you use the Set-ExchangeServer cmdlet. However, you should use caution when you use the Set-ExchangeServer cmdlet to exclude a domain controller from use. For example, if your domain has Domain_Controller_A and Domain_Controller_B, and you use the Set-ExchangeServer cmdlet to exclude Domain_Controller_A from use, Exchange Server stops working if Domain_Controller_B is not available.
You can also add the MinUserDC registry value to exclude the PDC emulator from use by the ADAccess component. When you use the MinUserDC registry value, you can set a minimum level of domain controller resources before the server that has the PDC Emulator role is enabled to handle Exchange requests. The MinUserDC registry value has the following advantages over using the Set-ExchangeServer cmdlet:
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/316300/ )Event ID 2080 from MSExchangeDSAccess
(http://support.microsoft.com/kb/812848/ )ISDN line makes connection to remote WAN sites every 15 minutes
For more information about the Set-ExchangeServer command, visit the following Microsoft website:
Article ID: 298879 - Last Review: March 23, 2012 - Revision: 7.0