Backup-to-disk (B2D) target file systems can become fragmented after extended use from Backup Exec.

Article:TECH83176  |  Created: 2009-01-25  |  Updated: 2012-10-04  |  Article URL
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Technical Solution



Backup-to-disk (B2D) target file systems can become fragmented after extended use from Backup Exec.


There is a possibility of increased fragmentation of file systems with backup-to-disk (B2D) folders located on them. A number of characteristics can contribute to whether significant fragmentation happens or not on file systems when using B2D. Certain Backup Exec configuration settings, usage, and workarounds may help the situation and are discussed below in this document.


    NOTE: There are many sources of possible fragmentation issues with NTFS volumes, it is possible that other applications may also be contributing to the increased fragmentation levels of NTFS volumes that may not be affected by these suggested changes specifically for Backup Exec.

Suggested Workarounds for Backup Exec include;


    1. Avoid hosting multiple backup-to-disk (B2D) folders on the same volume.
    2. Minimize the number of concurrent operations when backing up to disk by leaving the Concurrent operations" setting on the B2D folders "Configuration" screen at a value of 1.
    3. Maintaining at least 30% free space is recommended on volumes with B2D folders located on them. Avoid letting the volume that is hosting the B2D folder from becoming completely full.
    4. Avoid hosting files from other applications that also regularly grow and shrink repeatedly on the same volume as the B2D folders such as database files or their associated log files.
    5. Adjust your Backup Exec Overwrite and Append Period media management settings to preserve media as much as possible. This will force the use of available space and limit premature overwriting.
    6. Use existing Windows or 3rd party disk defragment tools to regularly defragment volumes containing B2D target locations. Please be sure to defragment the volumes when there is no backup activity taking place.

Symantec is also currently investigating long term solutions to improve how cluster allocations are managed for its B2D files to further reduce the possible fragmentation resulting from backup-to-disk operations with Backup Exec on NTFS volumes. Please check this document frequently for updated information on this topic as it becomes available.

Please also note that the new Backup Exec Continuous Protection Server (BECPS) application does not contribute to increased fragmentation of NTFS volumes and can also be used to backup data to disk. For more information on the new Backup Exec Continuous Protection Server, please see the website 




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