Database Mirroring = SQL Server 2016 AlwaysON Basic Availability Groups

Database Mirroring was one of the widely used feature since SQL Server 2005 until Microsoft announces Always On availability groups. Database Mirroring feature has been listed as deprecated ever since Availability groups have been introduced from SQL Server 2012.

SQL Server 2016 BOL states

Database Mirroring feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature. Use Always On Availability Groups instead.

What is Basic Availability Groups in SQL Server 2016?

Basic availability groups works like database mirroring to support the database mirroring in SQL Server 2016. Customer’s who use database mirroring then can still setup basic availability groups. Basic availability groups only works for

  • One availability database
  • No read access on secondary replica
  • No backups on secondary replica
  • No availability group listener
  • No support in an existing availability group to add or remove a replica
  • No support for upgrading a basic availability group to an advanced availability group

Despite these limitations, with a basic availability group you get benefits similar to database mirroring in addition to other features. For each replica, you can choose either synchronous-commit or asynchronous-commit mode as similar to database mirroring.

One good thing about this you can see better performance as it uses new transaction log transfer mechanism.

Hope you enjoyed the post!


Ramasankar Molleti

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About Ramasankar

My name is Ramasankar Molleti, I have been working on various database and cloud systems (SQL Server, Oracle, PostgreSQL, DynamoDB, Redshift, Amazon, Azure) over 12 years, primarily focusing on Architect , Development, Administration and Business intelligence. I hold various Certifications such as Amazon Web services Solution Architect Associate, Microsoft certifications (Microsoft Certified Information Technology Professional, Microsoft Certified Technology Specialist, and Microsoft Certified Solution Associate).
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