32bit MySQL on a 64bit linux

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  • 32bit MySQL on a 64bit linux


    I am trying to optimize the current settings of mysql and I've run across somewhere that one should make sure that the OS and MySQL are both 64bit... I currently have a 32bit MySQL running on a 64bit Fedora Core 7.. I am wondering as to what are the disadvantage/s of my current settings..

    Hope to hear from any of you...

  • #2
    One of disadvantages would be 3GB RAM usage limit since mysql deamon is just one process. So if your mysql needs more memory than that, you're in trouble.

    What was the reason you installed 32bit version on 64bit system though ?


    • #3
      Hi przemek, Thank you so much for your reply..

      We were using a 32bit machine before and when it was upgraded we weren't conscious enough that we also needed to have a new set of installers.. err

      I've more questions though..

      We're currently using MySQL 5.0.24 and the nearest version I could find with 64bit tar installer is MySQL 5.1.53. Would there be a great adjustment if we're gonna upgrade from MySQL 5.0.24 to 5.0.53?

      And if we're gonna stay with the 32bit MySQL, would it be safe to say that we could use the entire 3GB to MySQL and the rest can be used up by the OS and other processes? The 64bit machine are being used on a 24/7 basis that's why we're a bit hesitant to do an upgrade yet..

      Thanks a lot!


      • #4
        There are all 5.0 releases available at:

        However 5.1 seems a good way to go, I really do not recommend you to just upgrade and use it with current data.

        The proper way to upgrade would be to mysqldump all data from current instance and load that dump onto fresh 5.1 install (possible on another server) and if that happens without any problems you should be safe to use it's new data in production.

        I would also do that even when upgrading from 32bit old 5.0 to new 64bit 5.0.latest - this way you also get the all data optimized, and gonna be noticed if possible data corruption exists somewhere.

        Remember to do both file-based and sql backups before you start any migration.

        If you stay with 32bit, the system naturally can use the rest of memory for other processes, but I have no idea how mysql will behave once you reach mem limit, since I never use MySQL 32bit


        • #5
          przemek wrote on Thu, 09 December 2010 11:21
          ... but I have no idea how mysql will behave once you reach mem limit, since I never use MySQL 32bit
          Basically you get "Out of memory" errors from the mysqld process:

          101205 22:50:28 [ERROR] /usr/sbin/mysqld: Out of memory (Needed 1375668 bytes)

          And clients can be thrown out etc, etc.

          Which is the same way as if you run out of RAM on the machine or if you have a low ulimit setting that limits MySQL usage of RAM.


          • #6
            @przemek: Thanks for the link.. I wasn't able to find any 64bit installer for MySQL 5.0.24 though so I'm gonna try the 64bit MySQL 5.1.53 installer, following the steps you mentioned.

            @Mr. Sterin: Thank you so much for your input. With that I'll see to it that we'll be able to do an upgrade ASAP.

            To both of you, Thank you so much!!!