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Single witness server for Multiple (Principal / Mirror) pair servers RRS feed

  • Question

  • Can I use single witness server to monitor multiple pairs of (Principal / Mirror) servers ?

    eg.

    First set: Pri1, Mir1 (different servers)
    Second set: Pri2, Mir2 (different servers)
    Witness: Witserver (Same witness server for first and second set of servers)

    - How many databases (from multiple servers) can a single witness server support ?
    - Any performance issue if we use more servers ?
    - Can we use same port ?
    - Any best practices ?

    • Changed type bbsrini Thursday, June 11, 2009 4:31 AM question
    Tuesday, June 9, 2009 9:09 AM

Answers

  • A witness CAN serve multiple sets of mirrors.  In fact, a witness doesn't do much work, so you can feasibly serve quite a few with even a remotely capable witness.  YMMV, so testing is the best way to figure out how many pairs you can support.

    You can only have one mirroring endpoint, so you actually NEED to use the same port for all sessions.

    Hope this helps.
    Aaron Alton | thehobt.blogspot.com
    Thursday, June 11, 2009 5:10 AM

All replies

  • A witness CAN serve multiple sets of mirrors.  In fact, a witness doesn't do much work, so you can feasibly serve quite a few with even a remotely capable witness.  YMMV, so testing is the best way to figure out how many pairs you can support.

    You can only have one mirroring endpoint, so you actually NEED to use the same port for all sessions.

    Hope this helps.
    Aaron Alton | thehobt.blogspot.com
    Thursday, June 11, 2009 5:10 AM
  • Thanks Aaron. I will do some testing on this.
    Thursday, June 11, 2009 6:30 AM
  • There is no problem for single witness to support many mirroring pairs.
    More Servers mean more traffic to monitor - this one you should find out for your own.

    Take a look at - http://www.dbsnaps.com/articles/sql_mirror_1/
    Friday, June 12, 2009 6:56 AM
  • HI,

    THIS IS POSSIBLE, GO AHEAD.

    I have the same scenerio didnt find any issue. Find any issue then feel free to post.

    BR
    Praveen Barath

    --Marked as ANSWER if it helps--

    Thursday, June 18, 2009 11:38 AM
    Answerer
  • You sure can do that but beware that if that witness goes down it could be trouble. Remember witnesses have very few requirements (you can even use SQL express) so no real need to consolidate.

     

    Friday, June 26, 2009 7:44 PM
  • Thanks everyone for valuable inputs.
    Wednesday, July 1, 2009 5:19 AM