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MustGather: Reporting a performance issue that may happen in the future

How To


Summary

This document should be followed when anticipating a performance issue that may happen on your IBM i system. The document covers the following: performance questionnaire and collecting and uploading data.

Steps

WARNING: The data cannot be reviewed without a clear explanation of the problem.
A problem description of "everything is slow", lacks important details; use Step 1 to provide the required details.  
 
Step 1:  Required Performance Questionnaire   
  1. What needs to be fixed? For example, our payroll jobs, named ABCCO, are running one hour longer and causing service agreements to be exceeded.  The problem started after we applied PTFs on Sept. 15.
  2. What business function is impacted by slow performance on the system? For example, when payroll jobs do not complete by midnight, a financial impact occurs as the business is fined if payroll does not complete on pay day.
  3. To what extent has the performance of the business function changed and how is the slowness observed or measured? For example, a process used to complete in few minutes and now takes five hours to complete, causing night batch jobs (named ABCCO*) to run during daytime hours, leading to complaints from QPADEV* interactive users.
  4. What are the IBM i jobs (users or subsystems) responsible for processing the slow function? If you are not sure, what other information can you give us to identify the jobs in question?* For example, DRDA application is slow so focus on the QRWTSRVR jobs with user ID XYZ.
  5. What is the timeline of this issue? For example, we first noticed the problem on Sept 15th at 23:00, but the problem does not happen every night.  On Sept 16th, the job completed normally. We need the problem resolved by Sept. 30th (before the next pay day).
*If the issue appears to be system wide, pick an example of one important job or workload that is measurably slower and provide us with the details as a focus point.
 

Step 2: Verify the IBM Must Gather tool is installed and current before proceeding!
(If the tool cannot be installed or updated, follow the Related Information section for alternate data collection instructions.)
QMGTOOLS is a light-weight, noninvasive data collector tool provided by IBM.  The tool collects many logs and can take 30 - 60 minutes to complete.
  1. CALL PGM(QMGTOOLS/QGETVER) to display the build version. If it is more than three months old, proceed with step 2.
  2. QMGTOOLS/CMPVER then F6 = download and update
  3. If the QMGTOOLS library does not exist,  install the tool by using these instructions.
 
Step 3:  Collect data
Setup Job Watcher before the issue occurs and then collect SYSSNAP data after the issue occurs
  1. Verify Job Watcher PTFs are applied
  2. Create a library for the data:  CRTLIB IBMJW
  3. Alter the *NBRSEC to span the expected performance problem for a maximum of 7200 seconds. Shortly before the problem is expected to occur, use SBMJOB CMD(STRJW DFN(Q5SECSQL) COL(QMGRUN1) LIB(IBMJW) ENDCOL((*NBRSEC 3600) (*DASDMB 6096))) JOB(JOBWATCHER) JOBQ(QSYS/QSYSNOMAX)
  4. The JOBWATCHER job will automatically end after the *NBRSEC is reached, then, collect SYSSNAP data.
NOTE:  The light-weight QMGTOOLS/SYSSNAP command is non-invasive but can take several minutes to an hour or more to complete.  While the SYSSNAP command is running, ensure you complete the performance questionnaire in Step 1.
 
Use the following on the IBM i command line after the performance issue occurs:
CALL QSYS/QCMD
QMGTOOLS/SYSSNAP OUTPUT(*IFS) COLLECTDFT(Y) LICLOGS(Y) PALS(Y) QHST(N) COLDEVD(N) SRVDOCS(Y)  COLSQL(Y) COLPCSNAP(Y) CSDATA(Y) DAYSPRV(1) STRDATE(*CUR) ENDDATE(*CUR)  LIB2SAV1(IBMJW)
 
Step 4:  Instructions for Sending Data to IBM i Support
NOTE: If you are a Blue Diamond client, use this link for instructions on sending the data:
 
  1. The data will be stored in the IFS under the /tmp/SystemName_SYSSNAP_timestamp.zip directory.
  2. Use QMGTOOLS to send the data. NOTE: you need to set up a transfer id (and optionally store it in QMGTOOLS) to transfer the data via QMGTOOLS. 
  3. Use QMGTOOLS/FTP2IBMCMD, for example:  QMGTOOLS/FTP2IBMCMD FTPTYPE(*HTTPS) IBMID(transferID) IBMPWD(transferPWD) INPUT(*IFS) CASENBR(TSxxxxxxxxx) IFSFILE('/tmp/SYSNAME_SYSSNAP_202209272037.zip')
                                       
Reference:  https://www.ibm.com/support/pages/qmgtools-ftp-data-ibm
Alternate Methods:  https://www.ibm.com/support/pages/mustgather-instructions-sending-data-ibm-i-support
 

Document Location

Worldwide

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Document Information

Modified date:
22 January 2026

UID

ibm16417309

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