I have setup two node SQL 2012 Always ON cluster with file share witness. I have configured two networks, one for heartbeat and second for public.

My question is do I need a third network/ subnet for AG Listener?

Which network does the SQL user databases in the AG group use to replicate between the replica servers?

When I do the SQL backups, do I need to backup primary and secondary replicas or just backup the databases in the secondary replica?

Please advise.

 when you set up Availability groups - you should get a backup set wizard where you can setup how you want to your backups preferences..so, you backups will taken per that preferences.

however, irrespective of these preferences, you can always take backup either on primary or secondary. though you cannot take differential backup of secondary, you can only log backups on both the nodes and take full backup on primary and only copy_only full backup on secondary..

yes, you will configure another network for AG Listener. Refer this

https://msdn.microsoft.com/en-us/library/hh213080.aspx?f=255&MSPPError=-2147217396#DoesListenerExist

http://www.bidn.com/blogs/KathiKellenberger/sql-server/3977/what-is-the-alwayson-listener

Thanks. We use third party tool to backup. So i am thinking just take full backup of the secondary replica. Will that be sufficient?

My question was do i need a dedicated network for AG Listner? I understand i need to configure AG listener. My nodes already have two network cards configured, one for cluster heartbeat and another for public. 

Hi DNair,

As described in the Book Online article, for best performance, use a dedicated network adapter (network interface card) for AlwaysOn Availability Groups.  And you can review this blog to get more details about configuring a dedicated network for Availability Group communication.

Besides, regarding to the backup issue of AlwaysOn Availability databases, if you need to reduce or eliminate resource contention between production activity and backups, it is recommended to perform full database (copy only) backups as well as transaction log backups on the secondary replica. With full copy-only backups and subsequent log files, you are able to  recover database to a point in time. For more details, please review this blog:  Backing Up SQL Server Databases Participating In AlwaysOn Availability Groups.

Thanks,
Lydia Zhang

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