Availability Groups and Failover Cluster Instances

  • Hi everyone, I'm reading up on Always on and I am confused what is the difference between AlwaysOn Availability Groups and AlwaysOn Failover Cluster Instances. Can you shed some light on this? Thanks.

  • Availability Groups are a mechanism for setting up the ability to fail a database or a set of databases from one server to another. With this setup, there is nothing shared between the servers. They each have their own disks, their own CPU, etc. A cluster is at the server level. In a cluster, there is a shared disk between the two (or more) machines that each has to have access to in order for the service to work. You can get a lot more detail if you go and read the entries in the Books Online at MSDN.

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  • shahgols (3/21/2014)


    Hi everyone, I'm reading up on Always on and I am confused what is the difference between AlwaysOn Availability Groups and AlwaysOn Failover Cluster Instances. Can you shed some light on this? Thanks.

    Check my articles on this site here[/url] and here[/url] and here[/url]. Parts 3 and 4 will be published soon.

    Post back if you still have questions

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Thank you!

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