The scale-out backup repository can comprise one or more extents. The extent is a standard backup repository configured in the backup infrastructure. You can add any backup repository, except an object storage repository, as an extent to the scale-out backup repository.
The backup repository added to the scale-out backup repository ceases to exist as a backup repository. You cannot target jobs to this backup repository. Instead, you have to target jobs to the configured scale-out backup repository.
On every extent, Veeam Backup & Replication creates the definition.erm file. This file contains a description of the scale-out backup repository and information about its extents.
Extents inherit most configuration settings from the underlying backup repositories. The following settings are inherited:
- Number of tasks that can be performed simultaneously
- Read and write data rate limit
- Data decompression settings
- Block alignment settings
The following settings are not inherited:
- Rotated drive settings. Rotated drive settings are ignored and cannot be configured at the level of the scale-out backup repository.
- Per-VM backup file settings. Per-VM settings can be configured at the level of the scale-out backup repository.
Limitations, specific for certain types of backup repositories, apply to extents. For example, if you add Dell EMC Data Domain as an extent to the scale-out backup repository, you will not be able to create a backup chain longer than 60 points on this scale-out backup repository.
Extents of the scale-out backup repository should be located in the same site. Technically, you can add extents that reside in different sites to the scale-out backup repository. However, in this case Veeam Backup & Replication will have to access VM backup files on storage devices in different locations, and the backup performance will degrade.