CA TPX Session Management for z/OS

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TPX: D STOR shows Overflows but no single Slot has failed requests.

  • 1.  TPX: D STOR shows Overflows but no single Slot has failed requests.

    Posted 11-21-2016 08:47 AM

    You might see this behavior when issuing D STOR to see the current Storage usage:

     

    APU2ETPX - ****************** TPX Operator ************************* TEN0217

                                 Storage Statistics (Below 16M line)

    Open ACBs:  0342     Total ACBs:  1665   Terminals: 0179  Applications: 0702
    DSA  Bytes: 04440064 Current Use: 005 %  High Use:  006 % Free Areas:   0006
    Slot Bytes: 01441600 Current Use: 000 %  High Use:  002 % Overflows:   03541

    Slot   Size * Count = Bytes         Curr.Use   Max.Use Failed Requests
    01     00016  1024    16384           000 %     000 %  0      169363
    02     00024  680     16320           000 %     000 %  0      223109
    03     00032  1920    61440           000 %     006 %  0      22498
    04     00064  2560    163840          001 %     001 %  0      40436
    05     00072  1080    77760           000 %     000 %  0      4311
    06     00104  2008    208832          000 %     000 %  0      69783
    07     00128  928     118784          000 %     000 %  0      15917
    08     00512  928     475136          000 %     000 %  0      870202
    09     01024  56      57344           000 %     008 %  0      37530
    10     02048  40      81920           000 %     010 %  0      247378
    11     04096  8       32768           000 %     037 %  0      46869
    12     08192  16      131072          000 %     006 %  0      4069
    ***************************** BOTTOM OF DATA **************************

    No single Slot Request failed but there are 3541 Overflows. The answer is that if TPX needs a Slot from Pool 12 but these Slots are to small to fulfill the request the storage is taken from the DSA-Area of TPX and this event is marked as one Overflow. If you for example use TPXMAIL you need Slots of 10240 Bytes length. If Slot 12 contains only 8192 Bates long Slots (see above) no single request for TPXMAIL can be served from Slot 12.

    The solution is to use the Slot sizes recommended in the TPX manuals and no smaller ones.

    .



  • 2.  Re: TPX: D STOR shows Overflows but no single Slot has failed requests.

    Posted 11-21-2016 11:02 AM

    Hello,

    The CA TPX Session Management - 5.4 DocOps documentation contains useful information on this topic:

     

    Information about how to manage slot pool storage in CA TPX: 

     

    Best practices for changing slot storage parameters in CA TPX:

     

    Best, 

    Brandon Jenkins



  • 3.  Re: TPX: D STOR shows Overflows but no single Slot has failed requests.

    Posted 11-22-2016 01:54 AM

    Thank you jenbr05 Brandon for this additional information!

    Slot Pool tuning for TPX normally is not a big deal - you use the given defaults, run for a couple of days and then check the Storage usage with commands "D STOR" and "D STORXA". If some Slot Pools have Failures or are highly used, you can adjust the number of Slot Pools in the second and third panel of SMRT.