Overview
The Solution for Hosted Messaging and Collaboration version 4.0 documentation describes how to define the offline address book servers that host the offline address books for downloading by Microsoft Outlook client computers.
This documentation specifies that there may be a maximum of one thousand offline address books for each offline address book server. If you have to have more than one thousand offline address books, you must define a second offline address book server.
The OAB Resource Manager makes sure that additional offline address books are created on the second offline address book server.
How to increase the maximum number of offline address books
The maximum number of offline address books depends on the value of the
MaxPageSize attribute of the Lightweight Directory Access Protocol (LDAP) administration limit in the Active Directory directory service.
In Windows Server 2003, the
MaxPageSize attribute has a default value of 1000. To increase the maximum number of offline address books, you must perform both of the following actions:
- Increase the value of the MaxPageSize attribute to a value of up to 10000.
For more information about how to use the Ntdsutil tool to do this, click the following article number to view the article in the Microsoft Knowledge Base:
315071�
How to view and set LDAP policy in Active Directory by using Ntdsutil.exe
- Configure the OAB Resource Manager. Use the ModifyResources procedure in the Exchange 2007 OAB Resource Manager namespace to specify a new value for the capacity of an offline address book server.
Note You can use the ModifyResources.xml sample file that is provided with Solution for Hosted Messaging and Collaboration version 4.0.
After you increase the number of offline address books in your environment, you should monitor server performance to make sure that the modification has not adversely affected the server.
In particular, make sure that Active Directory searches that return lots of values do not take too long. Additionally, as the number of offline address books that are hosted on a particular server increases, verify that customers can still download updates to their offline address books in a timely manner, especially during peak working hours.
Note If you are currently using lower-specification servers to host the offline address books, you may want to consider upgrading to higher-performing servers. This is because after you increase the limit for the number of offline address books that may be hosted on the server, the load that the server experiences may be up to 10 times larger.
Important The effect of an offline address book server failure will be much larger if that server hosts many more offline address books.