GSLB - SQL Database replication RRS feed

  • Question

  • We have come across a requirement from one of our customer for hosting a mobile app for retail industry.


    Requirement as follows -


    1. Must have Active - Active DC-DR sites

    2. 30 ms max network latency between sites tolerable.

    3. GSLB for external traffic is required.

    4. Active-Active application and DB availability is required.


    We are looking for SQL database replication method which shall ensure active-active(readable) copy of database available on both sites with maximum of 60ms of replication lag.


    Please help me with replication/mirroring generally followed in GSLB cases

    Thursday, December 17, 2015 12:10 PM


  • Hi bharathsuresh,

    Firstly, SQL Server does not support load balancing.

    Secondly, based on your description, database mirroring is not suitable for your scenario, read-only queries cannot by executed against the mirrored database unless you create a snapshot on the mirrored database. If you use SQL Server 2012 Enterprise or later version, you can create AlwaysOn Availability Groups. Availability Groups is a super-charged database mirroring solution, it consist of a primary replica, where the primary databases are available for read-write from the clients; and one to eight secondary replicas, which optionally can be configured for read-only from the clients.

    Thirdly, replication is a publish-subscribe model. With transactional replication,  committed transactions made at the publisher can be distributed and applied immediately at the subscriber or at scheduled intervals. Real-time data availability can be achieved and the subscriber is readable. However, if a disaster occurs, you must manually switch servers by redirecting all the applications to the subscriber.

    For more details, please review the following articles.
    Database Mirroring (SQL Server)
    Transactional Replication

    Lydia Zhang

    Lydia Zhang
    TechNet Community Support

    Monday, December 21, 2015 3:35 AM