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AIX 6.1 TL9 SP1 has a known issue with paging space

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  • April 10, 2014 at 3:47 pm #54150
    Russ Ross
    Participant

      Long story short, you might want to consider avoiding AIX 6.1 TL9 SP1.

      We are running Cloverleaf 6.0 and when we upgraded from

      Russ Ross
      RussRoss318@gmail.com

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      • May 6, 2014 at 12:18 pm #80341
        Russ Ross
        Participant

          After failing back in PROD to the older stable OS level of

          AIX 6.1 TL8 SP3

          the unexplained paging growth stopped so really does point to the new OS level of

          AIX 6.1 TL9 SP1

          being plagued with the known issue reported from IBM that paging space once used does not get released even when the application releases it.

          the command

          lsps -a

          now shows paging space at 1% in PROD and 2% in TEST which more like what I’m used to seeing instead of rapid growth until it reaches 100% and system lock up.

          In TEST our system admins applied the recommended patch from IBM and paging space usage is holding steady at 2% now for 21 days which is starting to be encouraging that the problem has been identified and dealt with.

          One method to determine if you might have the problem with this on any AIX version is to shutdown all running hci processes and with nothing running you still see high consumption of paging space and only after a reboot does paging space get cleared.

          Our system admins have since reported back to me that this is not the only version of AIX that has the paging space problem and have also seen this in AIX 7.1 something.

          Russ Ross
          RussRoss318@gmail.com

        • July 7, 2014 at 4:25 pm #80342
          Max Drown (Infor)
          Keymaster

            From R&D,

            Quote:

            Description: It has been brought to our attention that there is a serious paging space issue in AIX 6.1 TL9 SP1 that can lead to paging space growing rapidly until the system crashes. This has been confirmed by IBM as a known bug, described as follows:

            **********************************************************

            * PROBLEM DESCRIPTION:

            * xmalloc garbage collector is not traversing all kernel

            * heaps, causing pinned and virtual memory growth.  This

            * can lead to low memory or low paging space issues,

            * resulting in performance degradations and, in some

            * cases, a system hang or crash.

            **********************************************************

            The full description from IBM can be found here:

            <a href="https://www-304.ibm.com/support/docview.wss?uid=isg1IV53582&#8243; class=”bbcode_url”>https://www-304.ibm.com/support/docview.wss?uid=isg1IV53582

            We thank the customer who has brought this issue to our attention and hope that all Cloverleaf customers will be able to avoid encountering catastrophic situations as a result.

            Resolution:

            Cloverleaf customers running on AIX are advised to avoid running on AIX 6.1 TL8 SP1 by either staying on a lower OS patch level or upgrading to a higher one.

            -- Max Drown (Infor)

          • July 8, 2014 at 1:34 pm #80343
            Bob Richardson
            Participant

              Greetings,

              Max and company, our Operating System folks have us on TL9 SP3

              and swap space usage is stable. (versus SP1)

              Also:  as an added note:  TL9 will be supported by IBM for the next 3 years.  We were at TL7 and support expires this October 2014.  By just upping the maintenance level this bought us the extra IBM support window.

              Hope this helps others on AIX.

            • July 8, 2014 at 5:17 pm #80344
              Russ Ross
              Participant

                We recent also upgraded to the next level up which was AIX 6.1 TL9 SP2 for us.

                IBM claims the fix for paging space was included at this level and above.

                I’m monitoring but certianly already looks to be better than AIX 6.1 TL9 SP1 that locked down paging space at a much faster pace and never released it.

                Russ Ross
                RussRoss318@gmail.com

              • July 9, 2014 at 7:51 pm #80345
                bill whatley
                Participant

                  Very timely info for us, as we were getting ready to go to TL9 in our test env.  Asking sysadmins to be sure to get SP2 and/or the patch.

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