Scale-Out Repository as NAS Backup Repository
If you use a scale-out backup repository as a backup repository for storing NAS backups, by default Veeam Backup & Replication evenly distributes backup data among all the performance extents added to this repository. The NAS backup data is accompanied by the metadata files. To provide an opportunity to restore data written to extents remaining available in case one or two of other extents are unavailable, Veeam Backup & Replication triplicates metadata when writing it to extents. Thus, every extent keeps metadata for data stored on this extent (in folder meta) and replica of metadata for data stored on adjacent extents (in folder metabackup). Even if two of three adjacent extents are lost, you can restore NAS backup data stored on the third extent.
Mind the following when storing NAS backups on a scale-out backup repository:
You can configure performance extents in a scale-out backup repository to act as data extents or as metadata extents. To do that, use the Set-VBRRepositoryExtent cmdlet, as described in the Veeam PowerShell Reference. As a result, NAS backup data will be written to the data extent, metadata will be written to the metadata extent.
Mind that even if the extent is intended for storing only backup data, replica of metadata for data stored on other extents will be copied to this extent.