Topic Last Modified: 2007-01-05
The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine the value for the msExchESEParamZeroDatabaseDuringBackup attribute of each storage group on the server. If the Exchange Server Analyzer finds the msExchESEParamZeroDatabaseDuringBackup attribute is set to 1, the Exchange Server Analyzer Tool displays a non-default configuration message.
The msExchESEParamZeroDatabaseDuringBackup attribute represents a configuration setting that enables the overwriting of deleted records/long values with zeros during backup. This is a process known as zeroing out. You can control the zeroing out of database pages at the storage group level. Each storage group can have a different policy for zeroing out deleted database pages.
By default, zeroing out is disabled and the value for the msExchESEParamZeroDatabaseDuringBackup attribute is set to 0. When the attribute is set to 1, deleted database pages are overwritten with other characters at the end of online backups of any of the databases in that storage group.
Enabling and disabling zeroing out for Exchange 2000 Server and Exchange Server 2003 can be performed using Exchange System Manager, as described in this article. Enabling and disabling zeroing out for Exchange Server 2007 can be performed using Exchange Management Shell, also described in this article. While this option provides greater security, it does affect server performance.
Note If you enable zeroing out on an Exchange 2000 Server computer, it is recommended that you install Exchange 2000 Server Service Pack 3 or a later version. Service Pack 3 corrects a known issue that can cause the Exchange information store to stop responding. For more information about this issue, see the Microsoft Knowledge Base article 320883, "XADM: The Information Store Stops Responding During an Online Backup If Database Zeroing Is Turned On" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=320883).
To enable or disable zeroing out for Exchange 2000 Server and Exchange Server 2003
Open Exchange System Manager.
Expand Servers, and then expand the server you want to modify.
Right-click the storage group that you want to change, and then click Properties.
In the Properties dialog box, select or clear the Zero Out Deleted Database Pages check box as needed. Selecting the check box enables zeroing out and clearing the check box disables zeroing out.
Click OK to save the setting.
Close Exchange System Manager, and then restart the Microsoft Exchange Information Store service for the change to take effect.
To enable or disable zeroing out of deleted pages for Exchange Server 2007
The following code is an example of the Set-StorageGroup command that enables or disables zeroing out for the databases in the 'MyStorageGroup' storage group.
Set-StorageGroup -Identity MyStorageGroup -ZeroDatabasePages $false Set-StorageGroup -Identity MyStorageGroup -ZeroDatabasePages $true
For more information about the affect on performance of overwriting deleted database pages, see the Knowledge Base article 815068, "XADM: Online Backup Performance Decreases Over Time" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=815068).