3 Replies Latest reply on Jan 21, 2009 5:34 PM by Clebert Suconic

    What is the purpose of the Journal files?

    glm Newbie

      I have a very simple program that has two classes, both generate JMS messages and both accept each others messages with onMessage() methods. If I delete all the files that are in my data/journal directory, after startup I find that the program by default generates 400Mgs of journal files (40 files 10Mgs each). These seem to be defined in the jbm-configuration.xml file at about lines 85 to 94, here is the snippit :

      <!-- 10 MB journal file size -->
      <journal-file-size>10485760</journal-file-size>

      <journal-min-files>40</journal-min-files>

      <!-- Maximum simultaneous asynchronous writes accepted by the native layer.
      (parameter ignored on NIO)
      You can verify the max AIO on the OS level at /proc/sys/fs/aio_max_nr. (aio-nr will give you the current max-aio being used)
      -->
      <journal-max-aio>5000</journal-max-aio>


      I a curious, is this really necessary (400 MGs minimum) and what is it used for?

      Regards,

      GMarsh