In Microsoft Exchange Server 2010, the following performance counters for monitoring the behavior of database defragmentation have been added for use with Performance Monitor:

• MSExchange Database ==> Instances \ Defragmentation tasks   Shows the background database defragmentation tasks currently executing.
  
  
• MSExchange Database ==> Defragmentation Tasks completed/Sec   Shows the number of background database defragmentation tasks completing execution per second.
  
  
• MSExchange Database ==> Defragmentation Tasks Discarded   Shows the background database defragmentation tasks that couldn't be registered.
  
  
• MSExchange Database ==> Defragmentation Tasks Pending   Shows the background database defragmentation tasks currently pending.
  
  
• MSExchange Database ==> Instances \ Defragmentation Tasks Scheduled/Sec   Shows the background database defragmentation tasks scheduled for execution per second.
  
  

These are informational performance counters to show the performance of the database and aren't required to be part of the daily maintenance of your database.

You can also enable extended Extensible Storage Engine (ESE) performance counters to further help with monitoring your databases. For more information, see How to Enable Extended ESE Performance Counters.

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Mailbox databases" entry in the Mailbox Permissions topic.

You can use the EMC to set the maintenance schedule for a database or allow 24x7 database maintenance. Online defragmentation no longer runs only during the maintenance window as it did in Exchange Server 2007. Instead, it's performed continuously as data is read from and written to the database. For more information, see New Exchange Core Store Functionality.

1. In the console tree, navigate to Organization Configuration > Mailbox.
   
   
2. In the result pane, on the Database Management tab, click the mailbox database for which you want to set the maintenance schedule.
   
   
3. In the action pane, under the name of the database, click Properties. The <Database Name> Properties dialog box appears.
   
   
4. On the Maintenance tab, select the Enable background database maintenance (24 x 7 ESE scanning) check box, and then click Customize to select a predefined schedule or to create a customized schedule.
   
   
5. Click OK to save your changes.
   
   

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Mailbox databases" entry in the Mailbox Permissions topic.

This example sets the database schedule for the mailbox database MailboxDatabase1 on Server01 to run between 02:00 and 03:00 on Sundays and Wednesdays.

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Set-MailboxDatabase -Identity "Server01\MailboxDatabase1" -MaintenanceSchedule "Sun.2:00-Sun.3:00","Wed.2:00-Wed.3:00"

This example mounts the database in 24 x 7 background check-summing mode.

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Set-MailboxDatabase -BackgroundDatabaseMaintenance $true -Identity <dbname>

When set to $false, the database will be mounted without the 24x7 checksum mode and will perform the ESE checksum maintenance during the online maintenance period that you selected.

For detailed syntax and parameter information, see Set-MailboxDatabase.

For more information about database maintenance, see the "Database Maintenance" section in New Exchange Core Store Functionality.