Applies to: Exchange Server 2007 SP2, Exchange Server 2007 SP1
Topic Last Modified: 2009-05-20

This topic explains how to enable and configure online maintenance database scanning in Exchange 2007 SP1 and SP2 by setting three registry subkeys. When online maintenance database scanning is enabled, Exchange performs the following steps:

  1. Reads in database pages

  2. Checksums the database pages. Checksumming is the process by which Exchange checks the integrity of a database by computing a value (a checksum) that depends on the contents of the database.

  3. If configured, performs page zeroing on the database pages. Page zeroing is a process that is performed at the end of a streaming backup in which the data within the database is overwritten with characters that you have selected for that purpose. This makes the data unrecoverable by conventional means.

Note   As a best practice, if you want to enable page zeroing on a database, you should do so when you create the database. If you do not configure page zeroing when you create the database, the first time page zeroing is run against the database, it will significantly impact server performance. The performance impact is considerably less after page zeroing has completed the first pass of the database. You can use throttling to limit the performance impact of the first page zeroing pass. For more information, see Online Maintenance Database Scanning in Exchange 2007 SP1 and SP2.

Before You Begin

To enable online maintenance database scanning, the account you use must be delegated the following:

  • Exchange Organization Administrator role

For more information about permissions, delegating roles, and the rights that are required to administer Exchange Server 2007, see Permission Considerations.

Also, before you perform this procedure, be aware of the following:

  • Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.

  • When page zeroing is enabled, allow more time for online maintenance and more log capacity for increased log traffic.

  • The throttling settings described in this topic are optional. These settings interrupt online maintenance database scanning for the specified number of milliseconds between every 320 kilobytes (KB) of input/output (I/O), thereby allowing the server to perform other tasks. When you enable throttling, the performance impact of the online maintenance database scanning process on the server is reduced. The default throttling setting is zero milliseconds (no throttling).

  • For more information about online maintenance database scanning, see Online Maintenance Database Scanning in Exchange 2007 SP1 and SP2.

Procedure

To enable online maintenance database checksumming

  1. Start Registry Editor.

  2. Set the following registry subkey (DWORD value) to a value of 1. (Create the subkey if it does not already exist.) HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\Online Maintenance Checksum

  3. To make your changes effective, restart the Microsoft Exchange Information Store service.

To set the throttling time interval

  1. Start Registry Editor.

  2. Set the following registry subkey (DWORD value) to the desired throttling interval in milliseconds. (Create the subkey if it does not already exist.) HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\Throttle Checksum

  3. To make your changes effective, restart the Microsoft Exchange Information Store service.

To enable online maintenance database page zeroing

  1. Start Registry Editor.

  2. If the following registry subkey exists, set it to a value of 1: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\Zero Database Pages During Checksum

  3. To make your changes effective, restart the Microsoft Exchange Information Store service.

For More Information

For more information about online maintenance database scanning, see Online Maintenance Database Scanning in Exchange 2007 SP1 and SP2.

For more information about monitoring online maintenance database scanning, see How to Monitor Online Maintenance Database Scanning in Exchange 2007 SP1 and SP2.