Before you add a storage system and start using storage snapshots for backup and restore operations, you must add a VMware vSphere server to the backup infrastructure. The VMware vSphere server is the vCenter Server or ESXi host with VMs whose disks are hosted on the storage system. For more information, see Adding VMware vSphere Servers.
It is strongly recommended that you add a vCenter Server or ESXi hosts to the backup infrastructure before you add the storage system. When you add the storage system, Veeam Backup & Replication performs the storage system rescan. As a part of this process, Veeam Backup & Replication maps storage volumes to VMware vSphere datastores. This helps Veeam Backup & Replication understand what VMs host their disks on storage volumes.
If you add the storage system to the backup infrastructure and do not add the vCenter Server or ESXi hosts, you will be able to perform only restore from storage snapshots. You will not be able to perform Backup from Storage Snapshots.
If you first add the storage system to the backup infrastructure and then add the vCenter Server or ESXi host, perform storage rescan to map storage volumes to VMware vSphere datastores.