How to keep servers up to date?

  • SwePeso

    SSC-Dedicated

    Points: 39693

    I have a server which is running fine in our primary location and we want to have a secondary location for failsafe reasons.

    Are there other options than Active/Passive cluster solution?

    What we want is that if the secondary location is activated due to a failure in the primary location and application is working against the secondary location and when primary location is fixed and started again, the application will be run against the primary location. The application will automatically decide which site to work against.

    Now to the question, how to get the information stored in the secondary location back to primary location when primary location is started again?

    Is the only answer an Active/Passive cluster solution?

    What we are thinking about as an alternative is a merge replication.

    I am also asking this question on SQLTeam.com


    N 56°04'39.16"
    E 12°55'05.25"

  • MarkusB

    SSC-Dedicated

    Points: 37369

    Did you look at database mirroring ? Seems to be the answer to your problem, unless you have loads of datatabases. Mirroring won't allow you to mirror more than about 50 databases on one server.

    [font="Verdana"]Markus Bohse[/font]

  • SwePeso

    SSC-Dedicated

    Points: 39693

    No, we haven't looked at database mirroring. Thank you for the tip!

    There are 5-6 databases of 15-20 gb each.


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    E 12°55'05.25"

  • MarkusB

    SSC-Dedicated

    Points: 37369

    Peso (6/3/2009)


    No, we haven't looked at database mirroring. Thank you for the tip!

    There are 5-6 databases of 15-20 gb each.

    The size is no problem.

    Check out for more information http://sqlcat.com/tags/Mirroring/default.aspx

    [font="Verdana"]Markus Bohse[/font]

  • SwePeso

    SSC-Dedicated

    Points: 39693

    Thank you again.

    I'll pass on the links to maintenance team for examination.

    Have a great day!


    N 56°04'39.16"
    E 12°55'05.25"

  • SwePeso

    SSC-Dedicated

    Points: 39693

    I have a follow-up question.

    The application is run on a desktop and when the application fails to connect to primary data site (for any reason), it will then try to connect to secondary data site.

    There are two data hosting companies they use. The databases are identical, they have decided to use this approach.

    If the application has used the secondary data site for a while and suddenly the primary data site is up and running again, they want to compare the two databases and make them identical again.

    Can database mirroring be used two-ways?


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    E 12°55'05.25"

  • MarkusB

    SSC-Dedicated

    Points: 37369

    With DB mirrroring, when the primary database becomes unavailable the mirror takes over the primary role. Once the first server comes online again it will automatically take over the mirror role and start to synchronize the changes from the new primary server. In mirroring monitor you can see what the status is and how far behind the mirror database is. Once the original server is synchronized you can switch roles if you want to.

    So there is no need to manually synchronize the original database.

    Only if the original database is unavailable for a very long time ( a couple of days or more), it might be better to restore a new database backup instead of synchronizing all the transactions.

    Hope this helps and I advise you to read through the mirroring section in BOL for more details.

    [font="Verdana"]Markus Bohse[/font]

  • SwePeso

    SSC-Dedicated

    Points: 39693

    Thank you very much for your insights and patience with me!

    I think maintenance team will have enough information now to stop "bugging" me, and you, any more for this matter.


    N 56°04'39.16"
    E 12°55'05.25"

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