Use the SYSMDUMP DD to Create a TPX SVC Dump
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Use the SYSMDUMP DD to Create a TPX SVC Dump

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Article ID: 268211

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Updated On:

Products

TPX - Session Management

Issue/Introduction

Broadcom Support recommends that you update your TPXPROC started task JCL in hlq.CB0VJCL to replace the SYSUDUMP DD 
statement with a SYSMDUMP DD statement. If a TPX internal failure occurs, SYSMDUMP writes a machine-readable dump 
of the system areas and the product address space to a data set, which Broadcom Support can use to troubleshoot 
the problem. 

Environment

Release : 5.4

Component : TPX for z/OS

Resolution

In your TPXPROC, replace the SYSUDUMP DD statement with the following SYSMDUMP DD statement:

 //SYSMDUMP DD DISP=(NEW,DELETE,CATLG),                        
//           DSN=&HLQ..TPXSTC.D&LYYMMDD..T&LHHMMSS..SYSMDUMP,
//           UNIT=SYSDA,SPACE=(CYL,(3000,200),RLSE),          
//           DCB=(RECFM=FB,LRECL=4160,BLKSIZE=0)
 

Consider the following items when using this DD statement:

  • The DISP parameter specifies (NEW,DELETE,CATLG) to allocate a new dump file 
     during the startup of a TPX region. This disposition automatically deletes unneeded
     dump files from normal runs and ensures that large amounts of space are not held for
     an empty file. 
  • The file name must be unique. We recommend using dynamic system symbols
    or in-house-defined JCL symbols in the DSN parameter. The sample DD statement 
    above uses &LYYMMDD and &LHHMMSS to insert the time and date. Alternatively, 
    generate unique file names by specifying the file name as a generation data set (GDS).
    If your job produces multiple abends, use the special SYS1.SYSMDPxx file to capture
    only the first dump.
  • If you use a DASD device, you can use the UNIT parameter to specify a group of esoteric devices.
  • SYSMDUMP dump files can use striping and compression. Striping writes the dump more quickly. 
    Compression reduces the file size (and therefore uses less I/O resources). You can also use
     extended format definitions or DSNTYPE=LARGE to accommodate large dump files.

 

Note: The size of the dump file depends on how much storage has been allocated to the MUF at the time of the dump.
          Because TPX dynamically allocates and releases storage as needed, you cannot calculate an absolute value.
          We have recently received dumps from 4,000 to 60,000 tracks (250 to 4,000 cylinders), with one file 
          using 81,000 tracks (5,400 cylinders). 

After you add the SYSMDUMP DD statement, test that it works:

  1. Edit the TPXPROC to change the REGION size to 2048K.
  2. Start TPX.
    An abend occurs, most likely a U0001.
  3. Verify that the abend created the SYSMDUMP file.
  4. Edit the TPXPROC to restore the REGION size to 0M.