Topic Last Modified: 2007-01-05

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine the value for the activationSchedule attribute on the mailbox stores and public stores. If the Exchange Server Analyzer finds that the value for activationSchedule resolves to Never, a warning is displayed.

The activationSchedule attribute represents the setting for the online database maintenance schedule. Online database maintenance in Exchange Server is very important. During this interval, tasks like dumpster cleanup (the deletion of messages that have passed their deleted item retention date), public folder expiry (messages in public folders that are older than a certain date are expired), deleted mailbox cleanup, and online defragmentation (database objects that are no longer being used are detected and removed, thereby making additional database space available) are performed. These processes keep the Exchange Server computer healthy and the performance stable. Online maintenance should be set to run at least four hours a day; failing to do so will cause performance degradation over time.

It is recommended that you configure online database maintenance to run on each database (mailbox store or public folder store) for four hours each day. Stagger the online maintenance intervals with the backup schedules. For example, if backup runs from midnight to 2:00 A.M., run online maintenance from 3:00 A.M. to 7:00 A.M.

This is important because online maintenance will not start if the backup session is still running. If an overlap occurs, backup takes precedence over maintenance. In this case, Exchange checks every 15 minutes to see if backup has completed. After backup completes, maintenance will start.

There are 18 tasks that the store goes through to run maintenance. When a task is started, it finishes the task regardless of the maintenance timing window. However, maintenance will not begin a new task if the timing window has expired. Thus, in some instances, not all tasks are completed in a given maintenance interval. If maintenance is cut short, it will pick up where it left off during the next maintenance cycle.

To enable online database maintenance for Exchange 2000 Server and Exchange Server 2003

  1. Open Exchange System Manager.

  2. Expand Servers, and then expand the server that you want to work with.

  3. Expand the storage group that you want to work with.

  4. In the list of available data stores in the details pane, right-click the store that you want to work with, and then click Properties.

  5. In the Store Properties dialog box, click the Database tab.

  6. Do one of the following:

    • In the Maintenance interval list, select an interval.

    • Click Customize to access the Schedule dialog box, and then create a custom interval.

  7. Click OK.

To correct this warning for Exchange Server 2007

  1. Open Exchange Management Console

  2. Expand Server Configuration and then select the server that you want to work with.

  3. Expand the storage group that you want to work with.

  4. Right-click the store that you want to work with, and then click Properties.

  5. On the General tab, click the Maintenance schedule drop down and select an interval, or click Customize to create a custom schedule.

For more information about online maintenance database tasks, see the Microsoft Knowledge Base article 159196 "XADM: Tasks Controlled by the IS Maintenance Schedule" (