Mirroring Monitor showing some null values RRS feed

  • Question

  • Hello. I have a problem with Mirroring Monitor.
    A pair of sql server 2008 R2 instances on separate servers (Windows 2008 R2 Datacenter (Virtual). One is the standby. 
    The environment  uses mirroring and log shipping. 2 databases are mirrored, both set up exactly the same.
    One provides all data via mirror monitoring, but the other does not, some figures are null.
    When I dig to see what is going on, I find that the second database does not have entries in sys.dm_os_performance_counters
    with object_name = SQL Server:Database Mirroring; on the second (standby) instance.
    The first database has 21 entries, as it should do.
    On the live instance, all entries are present, i.e. 21+21+totals = 63.
    I have been advised to look in the registry on the in-question' instance's server.

    I have done this, and only entry '009' is present in the expected place, so that is not the problem.

    Can anyone help as to why sys.dm_os_performance_counters is only being updated for one database being mirrored

    and not the other one.

    3 questions.
    1. Is the mirroring of 2nd instance databases working despite these missing entries for 1 database?
    2. What is the problem/cause?
    3. How can it be fixed?


    Wednesday, August 3, 2011 10:39 AM

All replies

  • Hi Andy,

    3 answers :-)

    1.Is the mirroring of 2nd instance databases working despite these missing entries for 1 database?

    I suspect it's not. What's the status showing for 2nd database when you expand databases folder in SSMS. It should be Principal,Synchronized.

    You can also run  


    * from sys.database_mirroring

    where you will find detailed info about database particapating in mirroring.

    2. What is the problem/cause?

    Have you got any error during mirroring set up for this database?

    Have you used the correct mirroring endpoint? A instance of sql server have one mirroring endpoint & it remains same for n number of databases on that instance?

    Database acting as principal have recovery model set to Full.

    3. How can it be fixed?

    Reconfigure the mirroring for that database by restoring the database backup on mirrored server with no recovery option and by applying any subsequent TLog backup with no recovery option and set the mirroring again.



    Regards, Vishal Srivastava
    Wednesday, August 3, 2011 12:28 PM
  • Hi Vishal,

    Thanks for replying.

    1. All indications are that mirroring is working on the suspect database, (principal, synchronized) on primary server

    and (mirror, synchronized / restoring) on secondary server. But maybe this is just happy that logs are passing over but the data file

    is not being updated, as in windows the date and time stamp on the data file is not changing.

    2. All setups worked perfectly, and recovery models are set to full.

    3. I am starting to agree that it may be best to start again setting up the mirroring. I will try at a suitable point.




    Wednesday, August 3, 2011 1:25 PM
  • What kind of warnings or errors have you observed during this operation?

    Satya SKJ, Moderator - SQL Server MVP [Knowledge Sharing Network - www.sqlserver-qa.net]
    Author of SQL Server 2008 R2 Administration cookbook.
    Follow me @sqlmaster.
    Monday, August 8, 2011 8:50 AM