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Veeam Backup & Replication 9.5
User Guide for Microsoft Hyper-V

Compact of Full Backup File

If you use a forever forward incremental or reverse incremental backup method, the backup job constantly transforms the full backup file in the backup chain to meet retention policy settings. The transformation process, however, has a side effect. In the long run, the full backup file grows large and gets badly fragmented. The file data occurs to be written to non-contiguous clusters on disk, and operations of reading and writing data from and to the backup file slow down.

To resolve the fragmentation problem, you can instruct Veeam Backup & Replication to compact the full backup file periodically. During the file compact operation, Veeam Backup & Replication creates a new empty file and copies to it data blocks from the full backup file. As a result, the full backup file gets defragmented and the speed of reading and writing from and to the file increases.

To compact the full backup file periodically, you must enable the Defragment and compact full backup file option in the backup job settings and define the compact operation schedule. By default, the compact operation is performed on the last Saturday of every month. You can change the compact operation schedule and instruct Veeam Backup & Replication to perform it weekly or monthly on specific days.

Compact of Full Backup File 

Limitations for Full Backup File Compact

The full backup file compact has the following limitations:

If such situation occurs, Veeam Backup & Replication triggers the full backup file compact operation during the next backup job session that produces an incremental backup file on another day.

Removal of Deleted VMs Data

During the compact operation, Veeam Backup & Replication does not copy all data blocks from the VBK file to the newly created file. It copies only data blocks of VMs whose information is stored in the configuration database. For example, if the VM is removed from the backup job, its data is not copied to the new full backup file. This approach helps reduce the size of the full backup file and remove unnecessary data from it.

VM Data Take Out

If the full backup file contains data for a VM that has only one restore point and this restore point is older than 7 days, during the compact operation Veeam Backup & Replication will extract data for this VM from the full backup file and write this data to a separate full backup file. Such backup will be displayed under the Backups > Disk (imported) node in the Home view.

The mechanism works if the following conditions are met:

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