Article ID: 840754 - View products that this article applies to.
When you use the Backup Configuration Wizard in Microsoft Windows Small Business Server (SBS) 2003 to perform a backup, the backup file may use more media space than you expect. If you are using a tape backup device, this problem may cause the backup procedure not to work, and the following entry may be logged in the backup log:If you are backing up to a hard disk drive, the backup procedure may not work, and the following entry may be logged in the backup log: This problem may occur after several successful backup procedures. Typically, this problem occurs while a backup is in progress. The problem does not occur immediately after the backup procedure starts. The problem does not occur every time that you try to back up the server.
Note If you cannot perform any backups in SBS 2003, and if the "The requested media failed to mount" entry is logged in the backup log, you may be experiencing an issue with tape drives that support different media block sizes.
For additional information about this issue, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/831664/ )"The requested media failed to mount" error message when you try to perform a backup in Windows SBS 2003
This problem occurs because the SBS Backup Configuration Wizard configures the Backup utility (NTBackup.exe) to perform an online backup of the Microsoft Exchange Server information store and to perform a file system backup of the MDBDATA folder. This configuration creates two backups of the information store because the MDBDATA folder contains the information store files.
When you plan the media requirements for your backup, calculate the tape space or the drive space that you must have to back up the file system and to perform the online backup of the information store. To calculate the space that you need, add the approximate size of the information store and the size of the volume that you are backing up. For example, if the volume that you are backing up is 50 gigabytes (GB), and if the information store is 10 GB, you must have about 60 GB to back up this volume.
To determine the approximate size of the information store, view the file sizes of the database files that contain the mailbox store and the public folder store. Add their file sizes together to calculate the total file size of the information store. By default, these files are named Priv1.edb, Priv1.stm, Pub1.edb, and Pub1.stm. The files are located in the C:\Program Files\Exchsrvr\Mdbdata folder. If these files are not in the default location, you can determine their location by using Exchange System Manager:
The SBS Backup Configuration Wizard configures an online backup of the information store and a file system backup of the MDBDATA folder because both types of backup procedures are useful for different disaster recovery scenarios. The MDBDATA folder backups are most useful for recovery if you must rebuild the server. For example, use this backup if you must replace or reformat the primary hard disk of the server because of a disk failure or because of a controller failure. The online backups of the information store are most useful for recovery when only the information store is damaged. For example, use the information store backup if the Exchange databases become inconsistent because of an unexpected shutdown, but the operating system is not damaged.
The online backups verify database consistency and remove log files that the information store is no longer using. If you do not run the online backups, the information store continues to generate new log files until you exhaust the free space on the volume that contains the log files.