To perform most data protection and disaster recovery operations, Veeam Backup for RHV uses workers. Workers are Linux-based VMs that are responsible for the interaction between the backup appliance and other Veeam Backup for RHV components. Workers process backup workload and distribute backup traffic when transferring data to backup repositories.
By default, the worker role is assigned to the backup appliance. However, this is sufficient only for small deployments with low traffic load. For large deployments, it is recommended to deploy dedicated workers as the embedded worker may not have enough bandwidth to process backup traffic. Deploying dedicated workers allows you to increase the maximum number of concurrent backup and restore operations, and to avoid high traffic load on the host running the backup appliance.
Each dedicated worker is launched on a specific host for the duration of a backup or restore operation. While configuring the worker, you can manually select the host or instruct Veeam Backup for RHV to choose a host automatically. Manual selection may be helpful if you want to avoid launching workers on specific hosts (for example, production ones), while automatic selection allows Veeam Backup for RHV to optimize data transfer and to balance the load on the hosts in the RHV cluster.
As soon as a backup or restore session starts, Veeam Backup for RHV launches a worker and test its configuration. Veeam Backup for RHV checks host affinity settings specified for the worker and chooses a host where the worker VM will run. Then, Veeam Backup for RHV powers on the worker VM and installs system updates (if available). When the backup or restore session completes, Veeam Backup for RHV shuts down the worker VM so that it can be used for other sessions later.