Repository considerations

Task consideration

A task at the repository level is consumed differently than tasks at the proxy level. If “per-VM backup files” is enabled on the repository, each concurrently processed VM will consume one repository task, while each virtual disk of this VM will consume one proxy task (the typical ratio is 3 disks per VM). On the opposite, if “per-VM backup files” is disabled, a single backup job will consume just one repository task regardless how many VMs are being processed by the job. But the number of consumed proxy tasks will stay the same (one task per each virtual disk).

Veeam® Backup & Replication™ does not apply the Limit maximum concurrent tasks option to back up repositories used as cloud repositories. For Veeam Cloud Connect Backup, the maximum allowed number of concurrent tasks is defined per tenant in the properties of the tenant account.

ReFS/XFS RAM allocation

When using the Windows ReFS filesystem, the recommendation is to add 0.5 GB RAM per TB of ReFS storage. However, you don’t have to scale this indefinitely. 128GB of RAM are often enough for task, OS and ReFS requirements if the total ReFS volume size of the server is below 200 TB. Depending on the ReFS size or task requirements, you may want to add up more memory but there should be no need to go over 256 GB.

When formatting your filesystem, use the below recommendations for the best performance:

https://helpcenter.veeam.com/docs/backup/vsphere/backup_repository_block_cloning.html?ver=100#linux

Beware that if you have multiple LUNs/RAIDs/Drives, you need to consider the total storage amount combined for that one OS.

https://bp.veeam.com/vbr/VBP/2_Design_Structures/D_Veeam_Components/D_backup_repositories/

Additional load

Also consider the impact backup copy jobs, SOBR capacity tier offload, and replica seeding will have on the repository. This will add I/O load when these jobs are scheduled to run and could also require data block rehydration before sending to the target location.