To retrieve VM data blocks from a SAN LUN during backup, the backup proxy uses metadata about the layout of VM disks on the SAN.
Data backup in the Direct SAN access transport mode includes the following steps:
- The backup proxy sends a request to the ESXi host to locate the necessary VM on the datastore.
- The ESXi host locates the VM.
- Veeam Backup & Replication triggers VMware vSphere to create a VM snapshot.
- The ESXi host retrieves metadata about the layout of VM disks on the storage (physical addresses of data blocks).
- The ESXi host sends metadata to the backup proxy.
- The backup proxy uses metadata to copy VM data blocks directly from the source storage over the SAN.
- The backup proxy processes copied data blocks and sends them to the target.