Can 'clustering' and 'alwayson failover clustering' be used interchangeably?

Question

I am reading this summary from the book 'Pro SQL Server 2019 Administration' from Carter.

In 'hot', when citing the examples the author writes 'Clustering'.

But when each technology is explained it is listed as 'AlwaysOn failover clustering'... My question is about naming: can the terms 'clustering' and 'alwayson failover clustering' be used interchangeably? or do they mean different things?

Answer 1

It depends in which context Clustering term is used

If we are talking about SQL Server, then Clustering means AlwaysOn Failover Clustering
When we are talking about Windows, Clustering means Windows Server Failover Cluster

My question is about naming: can the terms 'clustering' and 'alwayson failover clustering' be used interchangeably?

I would say - yes, these terms can be used interchangeably - BUT, you have to make sure you and whoever you are holding conversation with, understand in which context you use term Clustering - Windows or SQL Server

Answer 2

"Clustering" is definitely used here to refer to SQL Server's Failover Cluster Instances (FCIs). However, the terms are not interchangeable.

Both FCIs and Availability Groups (AGs) are built on top of Windows Server Failover Clusters (WSFCs). I've seen FCIs, AGs, and WDFCs referred to as "Clusters" or "Clustering." The correctness of referring to any of these simply as "Clustering" is debatable.

What isn't debatable is that referring to any of those technologies simply as "Clustering" is ambiguous and can be confusing without proper context. Using the more verbose terminology, or even in abbreviations will always be unambiguous.