Microsoft KB Archive/218004

= Circular Logging Prevents Backing Up Your Small Business Server =

Article ID: 218004

Article Last Modified on 11/19/2003

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APPLIES TO


 * Microsoft BackOffice Small Business Server 4.0
 * Microsoft BackOffice Small Business Server 4.0a
 * Microsoft BackOffice Small Business Server 4.5

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This article was previously published under Q218004



SYMPTOMS
During the installation of the Microsoft Exchange Server component of BackOffice Small Business Server, the Exchange Server computer is configured to use Database circular logging for the Exchange directory and information store. This is advantageous for users who don't use backup programs; however, incremental and differential backups cannot be performed on an Exchange Server computer if circular logging has been enabled.

When you try to perform a differential or an incremental backup of your Exchange Server computer with circular logging enabled, you will receive the following error messages:

Unable to attach to \\ \Microsoft Exchange Directory.

Unable to attach to \\ \Microsoft Exchange Information Store.

You may also receive these error messages if you perform a differential or an incremental backup of your Exchange Server computer prior to running a full backup.



CAUSE
A differential or an incremental backup of your Exchange Server computer was performed with Exchange Server configured to use Database circular logging.



RESOLUTION
Disable Database circular logging by using the following steps:


 * 1) Start the Microsoft Exchange Administrator program.
 * 2) Select the Exchange Server computer that you are attempting to back up.
 * 3) On the File menu, click Properties, and click the Advanced tab.
 * 4) Click to clear Database circular logging for both Directory and Information Store.

Perform a full backup of the Exchange Server computer, then differential or incremental backups of your Exchange Server computer can be performed.



MORE INFORMATION
With circular logging enabled, Exchange Server overwrites transaction logs, which prevents logs from being replayed in sequence after a restore of that backup tape if there is a problem. The restore process, with circular logging enabled, will only recover data up until the most recent backup was made. Any data since the last backup will be lost. You should never delete or move out log files manually.

More information regarding system backups and disaster recovery can be found in the disaster recovery white papers at http://www.microsoft.com/exchange.

