161 are occurring. Do not use a value greater than 9000, as that can corrupt transaction log files. Note: Log Record Stalls/sec is the number of log records that cannot be added to the log buffers per second because they are full. If this counter is non-zero most of the time, the log buffer size may be a bottleneck. You can configure the value for the msExchESEParamLogBuffers attribute using a tool such as the Active Directory Service Interfaces (ADSI) Edit snap-in, the LDP tool, or any other LDAP version 3 client. Caution: If you use the ADSI Edit snap-in, the LDP tool, or any other LDAP version 3 client, and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require that you reinstall Microsoft® Windows Server™ 2003, Microsoft Exchange Server 2003, or both. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk. 162 Procedure To configure the msExchESEParamLogBuffers attribute for Exchange 1. Start ADSI Edit. 2. Double-click the Configuration container, expand CN=Services, expand CN=Microsoft Exchange, and then expand CN=<ExchangeOrganizationName>. 3. Expand CN=Administrative Groups, expand CN=<AdministrativeGroupName>, and then expand CN=Servers. 4. Expand CN=<ServerName>, expand CN=InformationStore, right- click CN=<StorageGroupName>, and then click Properties. 5. In the Attribute Editor, click the msExchESEParamLogBuffers attribute, and then click Edit. 6. In the Edit Attribute box, set the value to 512 for Exchange 2000 Server or9000 (for example, clear the value) for Exchange Server 2003. 163 7. Click Apply, and then click OK. 8. Close ADSI Edit and then restart the Microsoft Exchange Information Store service for the change to take effect. For More Information For detailed information about the msExchESEParamLogBuffers Storage Group Attribute, see the Exchange Server Team Blog article, You Had Me At EHLO: msExchESEParamLogBuffers Storage Group Attribute at http://go.microsoft.com/fwlink/?linkid=64793. Note: The content of each blog and its URL are subject to change without notice. For more information about ESE log buffers, see Microsoft Knowledge Base article 328466, XADM: ESE Log Buffers That Are Set Too Low Can Cause the Store to Stop Responding. 164 For more information about how to use the LDP tool, see Microsoft Knowledge Base article 260745, XADM: Using the LDP Utility to Modify Active Directory Object Attributes. For more information about how to work with ADSI Edit, see the topic "Adsiedit.msc: ADSI Edit" in the Windows Server Help. How to Set the msExchESEParamMaxOpenTables Attribute for Exchange Server 2003 Exchange Server caches data about folders that are not currently being accessed. In some cases, this may contribute to virtual memory fragmentation. One way to mitigate this is to reduce the maximum number of database tables that can be open concurrently by modifying the value of the msExchESEParamMaxOpenTables attribute. The actual suggested value for the msExchESEParamMaxOpenTables attribute varies depending on the version of Exchange Server and the Exchange service pack that is installed. For Exchange 2000 Server Service Pack 2, the default setting for 8-processor servers is 85,000 tables per storage group. This is reduced to 27,600 in Exchange 2000 Server Service Pack 3 for 8-processor servers. For 4-processor servers, the value is 13,800. This value can be lowered to reduce virtual memory fragmentation issues. However, lowering this value could also cause situations where operations may fail because of too many open tables. 165 The error occurs because the maximum number of tables that could be concurrently open is being lowered, which means the maximum is reached sooner. Exchange Server 2003 uses a different method for caching data about folders that are not currently being accessed. Therefore, reducing the maximum number of open tables is neither necessary nor effective for reducing virtual memory fragmentation issues. This attribute should not be set on an Exchange 2003 server. Unless you have been instructed by Microsoft Product Support Services to enter a value here, use the ADSI Edit tool to clear the value set on this attribute. Before You Begin Important: If you use the ADSI Edit snap-in, the LDP utility, or any other LDAP version 3 client and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require you to reinstall Microsoft Windows Server™ 2003, Microsoft Exchange Server 2003, or both. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk. 166 Procedure To set the msExchESEParamMaxOpenTables attribute 1. Start ADSI Edit. 2. Double-click the Configuration container, expand CN=Services, expand CN=Microsoft Exchange, and then expand CN=ExchangeOrganizationName. 3. Expand CN=Administrative Groups, expand CN=AdministrativeGroupName, and then expand CN=Servers. 4. Expand CN=ExchangeServerName, expand CN=InformationStore, right-click CN=StorageGroupName, and then click Properties. 5. In the Select a property to view box, click msExchESEParamMaxOpenTables. 6. In the Edit Attribute box, click Clear to change the value to <not set>. 167 7. Click OK, and then click OK again. 8. Close the Active Directory editor and restart the Micros oft Exchange Information Store service for the change to take effect. For More Information For more information about this attribute, see Microsoft Knowledge Base article 325044, "HOW TO: Troubleshoot Virtual Memory Fragmentation in Exchange 2003 and Exchange 2000" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=325044). Migrating from Exchange Server 5.5 to Exchange Server 2003 This topic provides instructions for migrating your organization from Microsoft® Exchange Server 5.5 to Exchange Server 2003. Furthermore, because it is recommended that you run your new Exchange Server 2003 organization in native mode, this topic discusses the advantages of native mode, and provides instructions for switching from mixed mode to native mode. Specifically, this topic will: 168 Provide you with the information necessary to migrate your Exchange 5.5 mailboxes and public folders to Exchange Server 2003. Show you how to use the Microsoft Active Directory® directory service tools. Provide you with the requirements necessary to install Exchange Server 2003. Show you how to run ForestPrep. Show you how to run DomainPrep. Show you how to run Exchange Setup. Provide you with information about how to move mailboxes and public folders. Provide you with information about how to switch your Exchange Server 2003 organization from mixed mode to native mode. 169 You Cannot Install Exchange Server 2003 on the Same Server as Exchange Server 5.5 It is important to note that there is no option for performing an in-place upgrade from Exchange Server 5.5 to Exchange Server 2003. Specifically, you cannot upgrade a server running Exchange Server 5.5 to Exchange Server 2003. To upgrade your organization from Exchange Server 5.5 to Exchange Server 2003, you must instead install Exchange Server 2003 on a separate computer and then use Active Directory Connector (ADC) to connect it to your existing Exchange Server 5.5 organization. This process is detailed later in this topic. Permissions for Migrating from Exchange Server 5.5 to Exchange Server 2003 After ensuring that your organization meets the necessary prerequisites, the procedures referenced in this topic guide you through the deployment process. Table 1 lists the required permissions or roles for the procedures referenced in this topic. 170 Table 1 Procedures referenced in this topic and corresponding permissions Procedure Required permissions or roles Enable Microsoft Windows® 2000 Server or Microsoft Windows Server™ 2003 services See Windows 2000 or Windows Server 2003 Help Run ForestPrep on a domain controller (updates the Active Directory schema) Enterprise Administrator Schema Administrator Domain Administrator Local Machine Administrator Run DomainPrep Domain Administrator Local Machine Administrator . from Exchange Server 5.5 to Exchange Server 2003. Specifically, you cannot upgrade a server running Exchange Server 5.5 to Exchange Server 2003. To upgrade your organization from Exchange Server. migrating your organization from Microsoft Exchange Server 5.5 to Exchange Server 2003. Furthermore, because it is recommended that you run your new Exchange Server 2003 organization in native. about how to switch your Exchange Server 2003 organization from mixed mode to native mode. 169 You Cannot Install Exchange Server 2003 on the Same Server as Exchange Server 5.5 It is important