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  1. #1
    Join Date
    Apr 2013
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    Unanswered: Downtime while converting to mysql?

    Hello I am Alex

    I can't say that I am an expert on DBs, but I will be trying to convert an MS SQL DB to a MySQL DB soon.

    I will use the SQL ways tool, and I have a doubt that I hope someone can help me with.

    I want to convert from a MS SQL Db that is live and running without causing any downtime.

    My "newbie-question" is if I use a converting tool lets say SQLways or any other will I cause downtime?

    Thanks
    Alex

  2. #2
    Join Date
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    Of course.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

  3. #3
    Join Date
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    Not if you perform this operation as a side-by-side method. In-place conversion, as Blindman said, will result in downtime.

  4. #4
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    Apr 2013
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    Can you tell me how I perform a side-by-side conversion?
    If I want to avoid a downtime how can I do this?

    Witch tool do I use?

    Any suggestions

    Alex

  5. #5
    Join Date
    Aug 2004
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    Quote Originally Posted by xderpir View Post
    Can you tell me how I perform a side-by-side conversion?
    If I want to avoid a downtime how can I do this?

    Witch tool do I use?

    Any suggestions

    Alex
    Two identical servers built with same configurations. One remains on-line while the second one is built from MS SQL DB.

  6. #6
    Join Date
    Apr 2013
    Posts
    5
    Hi
    Thanks for your answer and pacience.

    Could you specify this further?

    I have one server online, it's the server that I want to convert to, the one I want to recieve my new mysql-DB.

    About the one built in MS SQL, do you mean that I should use an offline backup-file, build it in my MS SQL Editor?

    please give me a clue.

    Many thanks
    Alex

  7. #7
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    You are not going to avoid some down-time when converting a live system.
    Even if you bring the second system up in parallel, there will still be data continually flowing into the original system and that will have to be synchronized with the new system before the new system goes online. Then of course, there is also the physical cutover between the two systems which can't physically happen instantaneously.
    Finally, there is that fact that you will need to script out the cutover and rehearse it several times in order to make sure it runs smoothly, and you still won't have 100% confidence that there will be no glitches when the final cutover occurs. Realistically, you need to budget some time to deal with unforeseen events.
    Much better to just alert your users that the system will be unavailable for an hour starting at 1am some morning.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

  8. #8
    Join Date
    Apr 2013
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    blindman, you are refering to a in-place conversion right?

    what about the side-by-side conversion method?
    how do I do that? step by step anyone?

    thanks
    Alex

  9. #9
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    Apr 2013
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    Does anyone know any guide or walhthrough describing the method side-by side?

  10. #10
    Join Date
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    Alex, if you are talking about simply flipping a switch and suddenly everyone is using the new system with no loss of data from the old system they were using five seconds before, then this would be EXTREMELY difficult to pull off. You'd need to get a team of experience professionals to script the various components, set up a duplicates of both environments for repeated testing, etc.
    Sorry. There is no "step-by-step" guide for this.
    Either live with some downtime, or contract with a team of professional IT developers to handle your migration.
    If it's not practically useful, then it's practically useless.

    blindman
    www.chess.com: "sqlblindman"
    www.LobsterShot.blogspot.com

  11. #11
    Join Date
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    I've never done this, but I'm pretty sure that you could do it using N-tier app servers and SQL replication.

    Note that this is not for the faint of heart, it would take considerable expertise to do it with zero downtime and nearly anyone that could use both Microsoft SQL and MySQL could do it with a few hours of downtime.

    My first thought has to be "why?". This move makes no sense without more information about what is driving the move.

    -PatP
    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

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