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"Cross Mirroring" - any good? RRS feed

  • Question

  • Hi

    I’m about to move all our databases from an old lousy server to a brand new HP setup.
    I have 8 databases (total of approx 100Gb) and I get 2 BL25p servers and SAN access for them.

    Now, I want high availability and I like the idea of mirroring the databases for achieving that. On the other hand I don’t like the idea of the mirror server doing almost nothing while the principal gets the entire load – seems like a waste of good resources.

    But is this really the situation or mirror server also be loaded, just for being the mirror?

    Now, if the main load is on the principal would I then benefit from distributing the databases on both servers, so both servers would act like principal and mirror?


    What I mean is that server 1 could be principal for DB 1-4 while server 2 would mirror these DB’s and likewise serever 2 would be principal for DB 5-8 and server 1 would mirror them.

    Does it make sense? Would I benefit anything from this?

    Thx a lot
    Nicolaj

    Thursday, November 23, 2006 12:40 PM

All replies

  • In my experience i don't see any value to perform what you've referred, it is an opposite way of working in database mirroring. For the topic as mirror stays in loading state the application cannot be connected to perform the changes.

    You might think the root of mirroring and clustering in this case, which I believe another complicated scenario to setup and manage, because you cannot guarantee that mirroring will fail over after a cluster failover. .

    Monday, November 27, 2006 11:33 AM
  • Hi Satya

    I migt not have explained my idea very well :-)

    consider a setup with 2 databases. In order to split the load of these DB's they are installed on 2 different servers: DB1 on server1 and DB2 on server2.

    Now, in order to get failover DB1 is mirrored to Server2 and DB2 is mirrored to Server1. This way the load is distributed on 2 servers and the failover is ensured through mirroring.... i guess... (of course both servers should be able to handle the load of all DB running on them in case of a breakdown)

     

    But is this really the case, or will a server be too loaded just for beeing a mirror server?

     

    /Nicolaj

    Monday, November 27, 2006 2:04 PM
  • Yes, you can do that to get such option but I haven't come across such setup.
    Monday, November 27, 2006 8:04 PM
  • Hi Nicolaj,

    We are currently considering "cross mirroring" as you have described it - two database servers wit a total of 10-15 databases. I was curious if you have made it and do you have some positive exprerience? :-)

    Thank you very much,

     

    Regards,

    Zdravko

     

    Friday, December 8, 2006 1:54 PM
  • Hi Zdravko

    We are still some weeks from the actual implementation  , so I can't tell you about experiences yet. Sorry about that

    /Nicolaj

    Monday, December 11, 2006 9:33 AM
  • See this kBA http://support.microsoft.com/kb/926150 for the subject of cross mirroring or transactions basis.
    Thursday, December 21, 2006 2:41 PM