I would like to know what is the difference between Active Geo Replication and Auto Failover groups in Azure SQL DB ? I read that in Auto Failover groups, the secondary database is always created on a secondary region, but active geo-replication can happen between same region also. So when one should use compared to the other?
According to MSFT documentation - the Auto-failover groups "is a declarative abstraction on top of the existing active geo-replication feature, designed to simplify deployment and management of geo-replicated databases at scale". BCDR is the biggest use case - manual or automatic failover of SQL data to another region.
The auto-failover group feature imposes some limitations while adding convenience -