Database Mirroring Problems

  • Hi all..

    I have 2 server in mirroing... this morning i have to boot the mirror server and whens its up the message in mirror database was "restoring..." only.Before the message was something like (restoring, synchronized..etc)..now only "restoring..." . In principal server the message is "principal, synchronized"..but will be synchronized really ?

    When i configured this mirroring , this message in target server (only "restoring...") shows up when i restored the dabatase before starts synchronized doing de statments ALTER DATABASE XXX SET PARTNER in principal an target servers.

    I try to do this statments agains and shows up a error message

    Principal

    Msg 1405, Level 16, State 4, Line 1

    The database "SM" is already enabled for database mirroring.

    Target

    Msg 1452, Level 16, State 6, Line 2

    The partner server instance name must be distinct from the server instance that manages the database. The ALTER DATABASE SET PARTNER command failed.

    This servers are really synchronized ?

    $hell your Experience !!![/url]

  • Check the output of

    select * from sys.database_mirroring on principal database and verify whether the configuration is fine and mirroring state is synchronized or Synchronizing.

    You can also make use of database mirroring monitor and check the same(by registering your mirroring instances and see whether trafic is there when principal is getting updated).

    HTH,

    MJ

  • Thanks Manu...the select returns in columns

    mirroring_state mirroring_state_desc

    4 SYNCHRONIZED

    for all databases with mirroring

    can I presume that everything okay?

    $hell your Experience !!![/url]

  • Yes, you can presume that. Also, you can do one thing(if possible) to check this out:

    Do a failover when its okie and nobody will get affected. If it goes to mirrored database then it will confirm you to the fullest extent tht all is working fine under the hood.

    Manu

  • Thanks a lot Manu...

    $hell your Experience !!![/url]

  • I just spent 2 days trying to figure this out and I got it.

    On th Mirror reference the Primary server.

    ALTER DATABASE MYDB_04

    SET PATNER = 'TCP://PRINCPLESERVERNAME.DOMAIN.LOCAL:PORT#'

    On the Primary reference the Mirror server.

    ALTER DATABASE MYDB_04

    SET PATNER = 'TCP://MIRRORSERVERNAME.DOMAIN.LOCAL:PORT#'

    This is not stated correctly in the documentation the I have read.

    K9

  • Everyone PLEASE understand that database mirroring is an ADVANCED topic and you REALLY need to study up and practice with it in a test environment before pursuing it. Even better would be to engage a qualified consultant to help you a) understand what you HA/DR needs truly are and b) ensure you get there effectively and c) know how to troubleshoot/resolve issues that might crop up. You might just have your businesses very existence on the line here.

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

  • Hi Laerte

    It does sound as though your mirroring configuration is fine. Daft as it sounds, try doing a refresh of the tables in SSMS. This will probably fix the issue regarding not seeing "restoring, synchronized" against each database.

    For what it's worth, Kevin is absolutely spot on - mirroring is definitely an advanced topic. I played about in a test environment quite a bit, doing automatic failovers/manual failovers, turning servers off etc to see what would happen. It is not something I would recommend anybody should put into production until you are comfortable you can manage it correctly.

    Mike.

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