Uploaded image for project: 'Hadoop Map/Reduce'
  1. Hadoop Map/Reduce
  2. MAPREDUCE-3205

MR2 memory limits should be pmem, not vmem

VotersWatch issueWatchersCreate sub-taskLinkCloneUpdate Comment AuthorReplace String in CommentUpdate Comment VisibilityDelete Comments
    XMLWordPrintableJSON

Details

    • Improvement
    • Status: Closed
    • Blocker
    • Resolution: Fixed
    • 0.23.0
    • 0.23.0
    • mrv2, nodemanager
    • None
    • Incompatible change, Reviewed
    • Hide
      Resource limits are now expressed and enforced in terms of physical memory, rather than virtual memory. The virtual memory limit is set as a configurable multiple of the physical limit. The NodeManager's memory usage is now configured in units of MB rather than GB.
      Show
      Resource limits are now expressed and enforced in terms of physical memory, rather than virtual memory. The virtual memory limit is set as a configurable multiple of the physical limit. The NodeManager's memory usage is now configured in units of MB rather than GB.

    Description

      Currently, the memory resources requested for a container limit the amount of virtual memory used by the container. On my test clusters, at least, Java processes take up nearly twice as much vmem as pmem - a Java process running with -Xmx500m uses 935m of vmem and only about 560m of pmem.

      This will force admins to either under-utilize available physical memory, or oversubscribe it by configuring the available resources on a TT to be larger than the true amount of physical RAM.

      Instead, I would propose that the resource limit apply to pmem, and allow the admin to configure a "vmem overcommit ratio" which sets the vmem limit as a function of pmem limit.

      Attachments

        1. mr-3205.txt
          20 kB
          Todd Lipcon
        2. mr-3205.txt
          21 kB
          Todd Lipcon
        3. mr-3205.txt
          29 kB
          Todd Lipcon
        4. mr-3205.txt
          29 kB
          Todd Lipcon
        5. mr-3205.txt
          30 kB
          Todd Lipcon
        6. mr-3205.txt
          36 kB
          Todd Lipcon

        Activity

          This comment will be Viewable by All Users Viewable by All Users
          Cancel

          People

            tlipcon Todd Lipcon
            tlipcon Todd Lipcon
            Votes:
            0 Vote for this issue
            Watchers:
            14 Start watching this issue

            Dates

              Created:
              Updated:
              Resolved:

              Issue deployment