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AlwaysOn and Failover Clustering for HA\DR

  • February 2, 2017 at 11:55 am

    #334930

    Hi Friends,

    We are going to build a new SQL Server instance for which we will setup a HA\DR.

    SQL Server version is SQL Server 2014.

    The approach and steps I am thinking is to

    1. Build a multi-site cluster involving Primary Site(two nodes) and DR Site (one node)
    2. Configure a two node Failover Clustered Instance (FCI) on Primary Site for High Availability
    3. Install a standalone instance on DR Site node 
    4. Configure asynchronous AlwaysOn between FCI on Primary Site and Standalone instance on DR Site for the purpose of DR

    Questions I have are: 

    1. How many SQL Server licences I would require for this type of HA\DR setup?
    2. How many Windows licences I would require for this setup?
    3. Would it be better to configure a synchronous AG replica on Primary Site rather than having an FCI for the purpose of high availability? Would it impact by any means of performance\maintenance or licensing?

    Any help is greatly appreciated. 

    Thanks.

    Sujeet Singh

  • February 2, 2017 at 1:13 pm

    #1926453

    A) in general, "secondary" SQL Server instances that are not used for ANYTHING other than a failure of the primary do not require licensing. 

    B) Licensing is a VERY complex topic that you need 2 PhD's to decipher, and you will likely still wind up guessing. 🙂

    C) Synchronous mirroring will ABSOLUTELY carry a performance hit compared to a SQL Server Failover Clustered Instance. How much overhead depends on numerous factors.

    D) HA/DR is a VERY complex topic that also affects the very survivability of the company. We cannot guide you in the right thing to do without a substantial discussion about the company's needs, budgets and skillsets. Unless you really, REALLY know those things AND have substantial experience with ALL of the technologies involved I STRONGLY recommend you hire a person or company to assist you in this project.

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

  • February 3, 2017 at 8:27 am

    #1926622

    Divine Flame - Thursday, February 2, 2017 11:55 AM

    1. How many SQL Server licences I would require for this type of HA\DR setup?
    2. How many Windows licences I would require for this setup?
    3. Would it be better to configure a synchronous AG replica on Primary Site rather than having an FCI for the purpose of high availability? Would it impact by any means of performance\maintenance or licensing?

    1) At least two of the servers will have to be licensed, possibly all three, depends on a pile of things, speak with your MS licensing rep
    2) No clue
    3) Yes. No difference on licensing, but it's simpler to manage, one technology not two, and you get the advantage of not having a single point of failure in your HA - that of the storage.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • February 21, 2017 at 2:47 am

    #1929478

    Thanks Gail & Kevin for the help.

    Sujeet Singh

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