The difference between Azure back up and Site recovery is as below
Site Recovery manager : The feature addition allows companies to protect its on-premises, heterogeneous systems.
Built on the technology obtained as part of the In Mage Systems acquisition, advantages include:
- Protection of physical Windows or Linux servers.
- Simple replication, failover, and recovery using the Azure Site Recovery portal.
- Data replication over the Internet, a site-to-site VPN connection, or over Azure ExpressRoute.
- Failback (restore) from Azure to an on-premises VMWare infrastructure.