Achieving Server Redundancy at Remote Offices

  • Mark F. Cook

    Mr or Mrs. 500

    Points: 542

    sorry, posted this earlier but apparently i had some issue with my connection. anyway, to be completely honest, we probably should have included it as an option. we were/are aware that its was possible to use replication in this way, but most of what we read in posts, etc steered us away from using it for failover.

  • Charles Tsang

    SSC Enthusiast

    Points: 134

    On a course I was on, the passive server in a database mirroring setup for SQL2005 was said to be acting in unlicensed mode. This would mean that full functionality was not available (reporting/analysis).

    Have you found this to be the case for your situation where the passive server is unlicenced?

    Charles

  • Mark F. Cook

    Mr or Mrs. 500

    Points: 542

    There isn't any real limitation to the functionality of MSSQL with log shipping - at least not the "roll your own" kind i've used in the past. In my experience with log shipping (SQL2K), the destination database can be accessed by users in between the times when logs are restored to it. At that point, user connections have to be killed as the database needs to be in single user mode.

    My understanding of licensing is that if the destination server is used only for failover, a second license isn't required. However, if you allow users to connect to it, i would think a second license would be necessary.

  • netmikem

    SSCarpal Tunnel

    Points: 4000

    Hi Mark.

    This topic is dear to my heart these days as I've recently been charged with BCP for our firm.

    One of the guys working with me suggested the use of a CNAME DNS entry to achieve something similiar to what you did with the IP address solution. The idea is to have a generic server name that can be resolved to a real machine name and in the event of the production server going down, you simply change the CNAME entry to the secondary machine.

    For example, consider the following configuration. The production database server is named PROD and the failover one is called EXTRA. You would create a CNAME DNS entry named DBSERVER and point it to PROD.

    All applications would be configured to connect to DBSERVER.

    If PROD ever went offline unexpectedly, you would change the CNAME DNS entry for DBSERVER from PROD to EXTRA.

    We've tested it and it seems to work like a charm.

    I'm interested to know if you considered this approach but decided the IP address strategy was better for some reason?

    Regards,

    - Mike

  • Mark F. Cook

    Mr or Mrs. 500

    Points: 542

    Mike

    it sounds like a good approach but one we never considered. I'll be interested in trying it at some point.

    thanks

    mark

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