This article's content was written for Veeam Backup & Replication 11a and older.
Starting in Veeam Backup & Replication 12, Rebalancing Extents of Scale-Out Backup Repositories is a built-in feature.
Read about all the new features in Veeam Backup & Replication 12 in the What's New document.
The metadata file (VBM) contains information about the backup job, VMs processed by the backup job, number and structure of backup files, restore points, etc. When a rescan operation is done for a Scale-Out Backup Repository (SOBR), the Veeam Backup & Replication software will look through all folders of each extent for vbm (Metadata) files. These VBM files indicate to the software that files may be in the folder with that VBM. The software will then scan the files in the same folder and record their location in its database.
Because the VBM only indicates that file may be in the folder next to it, it is possible to move any file for a given backup chain from/to any extent. Furthermore, it is possible to move files from different extents to a single extent, as long as the folder paths match and the VBM is in the folder.
Backup files moved between extents of a SOBR must always be placed in the same relative folder structure to the path of the extent.
The Scale-Out Backup Repository below is named "SOBR," there are 2 extents, “SOBR Extent 1” and “SOBR Extent 2”. Their "repository paths" are different, but if files are to be moved between them, the subfolders in those paths must remain the same.
In this example, "SOBR Extent 1" has a path of E:\VeeamBackup\, and "SOBR Extent 2" has a path of C:\Backups\. If the backup files are initially in E:\VeeamBackup\DailyBackup when they are moved to SOBR Extent 2, they must be placed in a folder named "DailyBackup" (C:\Backups\DailyBackup).
If a new extent is added to the Scale-Out Backup Repository, and you want to move some/all of the files from the existing extents, you would have to create the same folder structure. Then place a copy of the vbm from any other extent, and proceed with moving the files you intend to move to this extent.
For example, if an NFS share were added as the third extent of the SOBR example above with a path of backupnas:/backups/, then the full path to the manually moved backup files would have to be backupnas:/backups/DailyBackup/ for the files to be recognized correctly.
Note that for Cloud Connect environments, there is a PowerShell commandlet available which can be used to perform an individual tenant evacuation from a specific extent. https://helpcenter.veeam.com/docs/backup/powershell/start-vbrcloudtenantbackupevacuation.html
Please keep in mind the following regarding ReFS Fast Clone and SOBR:
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