What About Database Mirroring and Replication?

Database Mirroring (DBM) was deprecated in SQL Server 2012. Its official replacement is AGs and they were documented as such when SQL Server 2016 introduced basic Availability Groups and the ability to use AGs with certificates. While DBM still ships as part of SQL Server 2019 for Windows Server (not Linux), it should not be used for new deployments. Microsoft often no longer removes deprecated features. Customers upgrading from previous versions of SQL Server, where DBM was the main business continuity strategy, should migrate to AGs.

Replication is not an official business continuity feature in the same way that AGs, FCIs, and log shipping are. However, it can be used to enhance the availability of data and many still use it in this capacity. Consider a scenario where executives need access to data. They may not need the whole database, but a subset. Replication enables this scenario – the schema can be different, have a different...