Home > SQL Server 2012 > Compare SQL Server 2012 Always On Technology with other high availability feature like Mirroring, Log shipping and clustering and why it is more acceptable.

Compare SQL Server 2012 Always On Technology with other high availability feature like Mirroring, Log shipping and clustering and why it is more acceptable.


Here I have mentioned some reasons why SQL Server Always On technology  is a good high availability option as compared with other high availability features like Mirroring, Log shipping and clustering.. SQL Server 2012 now has Always On technology, where the database can keep mirror copy/copies of the database that are constantly being refreshed.  In the event of a failure of the Primary, it will seamlessly fail over to another copy. SQL Server 2012 Always On is employs mirroring and clustering together to achieve the high availability

 

 

SQL Server 2012 Always On — SQL Server Mirroring

This has significant disadvantages over traditional SQL Server Mirroring.

  • In traditional mirroring we cannot manage groups of databases, so that when a single database failed they would all failover.
  • There is only one Mirror of the database allowed
  • The Mirror is not useable unless you are prepared to work with Snapshots.

 

  • In SQL Server 2012 Always On Technology,  we have Availability Group option, using which Databases can now be grouped together. When a failure happens, the entire group of database is treated as one. When one fails over they all fail over. This is very powerful when you have an application that uses more than one database in an instance.

 

SQL Server 2012 Always On — SQL Server Log Shipping.

 

Log shipping is sort of manual mirroring which allows more than one replica to be kept; perhaps a local one and a remote one.  This is more difficult to setup and failover is not automatic The biggest downfall is we  cannot use the receiving database since it is in a recovery state  and  read-only  as the transaction logs are being applied. In  SQL Server 2012 Always On Technology all the databases can failover automatically.

 

SQL Server Always On Versus SQL Server Clustering.

With SQL Server clustering, you are dealing with a shared storage system that adds cost and complexity to the equation.  AlwaysOn doesn’t need to use shared storage. So here it is more cost effective.

 

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  1. December 24, 2012 at 7:56 pm

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