Question & Answer
Question
How do I set up and use HSM's log data set?
Cause
Customer wants to use HSM's Log data sets. The DFSMShsm log data sets provide information about DFSMShsm events on a particular processing unit and about commands that are entered with the LOG command.
Answer
The log data sets provide information about HSM events on a particular processing unit and about commands that are entered with the log command. The information is recorded in chronological order. However, the SMF and the problem determination aid data sets already record much of the information contained in the log. If you are keeping SMF and PDA data and you do not have an ISV product that scans the LOGX/LOGY files, the HSM log is not needed. Specify DD DUMMY and use the HOLD LOG command.
LOG data sets can be SMS-managed or non-SMS managed. If you decide to SMS-manage them, you must use GUARANTEED SPACE. It is recommended that you assign them to a management class that does not perform MIGRATION, BACKUP, Partial Release=N and the Expiration Attributes are set as NOLIMIT.
Here is an example of an allocation for non-SMS-managed LOG data sets:
//HSMLOGX DD DSN=?UID.HSMLOGX1,DISP=(,CATLG),UNIT=?LOGUNIT,
// VOL=SER=?LOGVOL,SPACE=(CYL,(3))
//HSMLOGY DD DSN=?UID.HSMLOGY1,DISP=(,CATLG),UNIT=?LOGUNIT,
// VOL=SER=?LOGVOL,SPACE=(CYL,(3))- LOG data sets can also be allocated on SMS-managed volumes, but they cannot be extended format.
- LOG data sets can also be allocated as DSNTYPE=LARGE on both SMS-managed and non-SMS-managed volumes.
Both log data sets must be allocated on the same volume. The size of the data sets depends on how busy your system is and how much trace information you want the log to contain. You can tune the size of the log data sets by monitoring for ARC0027I messages while log is enabled. HSM generates an ARC0027I message each time the log data sets fill and swap. Tune the size of the LOGX and LOGY data sets until the log data sets swap at an acceptable rate.
To enable logging events in the log data sets, do the following:
1. In the HSM STARTUP PROC, specify ARCLOGX and ARCLOGY DDs pointing to pre-allocated data sets per sample.
2. In the HSM STARTUP PROC, to automatically swap the DFSMShsm log data sets at startup, specify LOGSW=YES.
3. In the HSM ARCCMDxx PARMLIB member, ensure the command HOLD LOG is not specified.
4. While HSM is processing, the log can be held:
HSEND HOLD LOG
HSEND RELEASE LOG
The log data sets are manually swapped with the command:
HSEND SWAPLOG LOG
3. In the HSM ARCCMDxx PARMLIB member, ensure the command HOLD LOG is not specified.
4. While HSM is processing, the log can be held:
HSEND HOLD LOG
HSEND RELEASE LOG
The log data sets are manually swapped with the command:
HSEND SWAPLOG LOG
You can retain log trace information for days, weeks, or months with an auto-op program and a GDG:
1. Allocate a GDG to hold the contents of the LOGY data.
2. Create a job that copies the LOGY data set into the GDG that you allocated in step 1.
3. Set up an auto-op job to run the job from step 2 when an ARC0027I message is received. The ARC0027I message is generated by HSM when the LOGX and LOGY data sets are swapped.
Ensure that the log data sets are large enough so the auto-op job completes before HSM needs to swap the log again. If HSM attempts to swap the log while the job is copying the LOGY data set, log tracing fails.
Ensure that the log data sets are large enough so the auto-op job completes before HSM needs to swap the log again. If HSM attempts to swap the log while the job is copying the LOGY data set, log tracing fails.
You can use ARCPRLOG and ARCPREDIT utilities to print and format the LOGY data sets or backup of LOGY data sets.
For more information:
z/OS® DFSMShsm Storage Administration
Printing DFSMShsm log information
Printing DFSMShsm log information
For "Setting Up the HSM Problem Determination Aid (PDA) Facility" see following technote:
https://www.ibm.com/support/pages/setting-hsm-problem-determination-aid-pda-facility
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Document Information
More support for:
z/OS
Component:
DFSMS->HSM->General
Software version:
All Version(s)
Operating system(s):
z/OS
Document number:
6243908
Modified date:
18 October 2024
UID
ibm16243908
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