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placement of witness server RRS feed

  • Question

  • hi

    i am looking for some advice on the placement of a witness server

    i have 1 office with a comms room and a DR site

    i have 1 sql server which is mirrored with a sql server in the DR site. 1 database (blackberry server database) is mirrored between these 2 sql servers. (windows 2008r2 and sql 2008r2

    i have also configured a witness server (sql express 2008r2) and have placed it in the DR site. automatic failover is working fine.

    there is 1 flaw with this setup, yesterday i had to reconfigure the switch in the DR site and all the servers (including the sql server) were shutdown.

    the principal sql server in the office went offline as the quorom was broken, the solution would be to place the sql witness server in the office rather than in the DR site but that would mean if the office site would become unavailable i could not failover to the DR site sql server as the witness server would not be able to communicate with the mirror sql server telling it to become the principal.

    does anyone have any idea how i could solve this issue?

    many thanks

    Thursday, October 14, 2010 9:10 AM

Answers

  • The only way to safely support automatic failover in the event of a site loss is to place the witness server in a 3rd location that has connectivity back to both the primary and DR site.  You already experienced why it is not a good idea to place it in the DR site and you can imagine what would happen if you placed in in the primary site and you had a complete site loss.
    David A. Bermingham, MVP Senior Technical Evangelist, SteelEye Technology
    Thursday, October 14, 2010 2:59 PM

All replies

  • check the following article to ADD / REPLACE mirror server:

    http://technet.microsoft.com/en-us/library/ms365603.aspx

    HTH

    Thursday, October 14, 2010 11:54 AM
  • The only way to safely support automatic failover in the event of a site loss is to place the witness server in a 3rd location that has connectivity back to both the primary and DR site.  You already experienced why it is not a good idea to place it in the DR site and you can imagine what would happen if you placed in in the primary site and you had a complete site loss.
    David A. Bermingham, MVP Senior Technical Evangelist, SteelEye Technology
    Thursday, October 14, 2010 2:59 PM
  • i had considered a 3rd site before

    if i put the witness server in a 3rd site (i have 2 options so that is not an issue) but for some reason the 3rd site goes down and due to some real bad luck either the primary or the secondary site goes down is there a manual override to at least bring the previously mirrored database (either the original principal or mirror database) back online via a manual intervention.

    when i had lost the DR site (with mirror and witness) i could not alter the principal database as it goes into "principal, disconnected / in reovery" state and you cannot make any changes to it

    is there some kind of procedure to follow which would allow me to bring it back online again?

    many thanks

     

     

    Friday, October 15, 2010 11:19 AM
  • I am not a DBA, but this thread seems to answer the question...

    http://social.msdn.microsoft.com/Forums/en/sqldatabasemirroring/thread/40e6b7b2-2d17-4254-8bd4-d2293f3b2a14

     


    David A. Bermingham, MVP Senior Technical Evangelist, SteelEye Technology
    • Proposed as answer by butre Friday, October 15, 2010 1:32 PM
    Friday, October 15, 2010 12:53 PM