Component TRACE (CTRACE) is the z/OS system trace capability for z/OS components. Most z/OS components use it.
From “capturing a trace” perspective, there are two aspects.
- Capturing the trace data
- The trace can be an in-memory trace, which is available when a dump is taken. This is is often the default. For example by default a trace is enabled to capture errors, and the in-memory trace is used.
- You can have a trace writer started task which writes to a data set. When you start the trace you give the name of the started task. Data is passed to the trace writer job. You can then use the trace data set in IPCS.
- Enabling the trace for the component. Usually there are options you can specify, for example all entries, or just error entries and how big the in-memory trace should be.
To trace a z/OS component, you need to know the CTRACE component name, and what you want to trace.
I tried to capture a CTRACE of a z/OS component, and struggled, because I didn’t know the name of the component.
What are the trace component names?
The z/OS command
TRACE STATUS
gave
IEE843I 16.10.22 TRACE DISPLAY 940
SYSTEM STATUS INFORMATION
ST=(ON,0001M,00005M) AS=ON BR=OFF EX=ON MO=OFF MT=(ON,064K)
COMPONENT MODE COMPONENT MODE COMPONENT MODE COMPONENT MODE
--------------------------------------------------------------
CSF ON NFSC ON SYSGRS MIN SYSANT00 MIN
SYSJES2 SUB SYSRRS MIN SYSIEAVX MIN SYSSPI OFF
SYSJES SUB SYSHZS MIN SYSSMS OFF SYSAXR MIN
SYSDLF MIN SYSOPS MIN SYSXCF MIN SYSDUMP ON
SYSLLA MIN SYSXES ON SYSUNI OFF SYSCATLG MIN
SYSTTRC OFF SYSTCPDA SUB SYSRSM SUB SYSAOM MIN
SYSVLF MIN SYSTCPIP SUB SYSLOGR ON SYSOMVS MIN
SYSCEA MIN SYSWLM MIN SYSTCPIS SUB SYSTCPRE SUB
SYSIOS MIN SYSANTMN MIN SYSDMO MIN SYSIEFAL ON
SYSTCPOT SUB
I was after a CEA trace, and from the above, the name is SYSCEA. It is MIN, so is already active.
What is the trace’s status?
d trace,comp=SYSCEA
gave me
COMPONENT MODE BUFFER HEAD SUBS
-------------------------------------------------------------
SYSCEA MIN 0002M
ASIDS *NONE*
JOBNAMES *NONE*
OPTIONS ERROR
WRITER *NONE*
So it is active, capturing errors, and writing to the in-memory trace (because there is no WRITER). I recognised the options as the defaults in parmlib member CTICEA00.
I had my own trace writer started task
Member CTWTR in proclib
//CTWTR PROC
//DELETE EXEC PGM=IEFBR14
//TRCOUT01 DD DSNAME=IBMUSER.CTRACE1,
// SPACE=(CYL,(10),,CONTIG),DISP=(MOD,DELETE)
//*
//IEFPROC EXEC PGM=ITTTRCWR,TIME=999
//TRCOUT01 DD DSNAME=IBMUSER.CTRACE1,
// SPACE=(CYL,(10),,CONTIG),DISP=(NEW,CATLG)
//SYSPRINT DD SYSOUT=*
I started my CTRACE writer
TRACE CT,WTRSTART=CTWTR
I created my own member CTICEACP in parmlib
TRACEOPTS
ON
BUFSIZE(20m)
OPTIONS('ALL')
WTR(CTWTR)
The WTR ties up with my CTRACE writer started task name.
Stop the current trace
TRACE CT,OFF,COMP=SYSCEA
Start the CEA trace using my member
TRACE CT,ON,COMP=sysCEA,PARM=CTICEACP
Run the test
Stop the CEA trace
TRACE CT,OFF,COMP=SYSCEA
Stop the trace writer
TRACE CT,WTRSTOP=CTWTR
The output from the CTWTR task gave me
IEF196I IEF142I CTWTR CTWTR - STEP WAS EXECUTED - COND CODE 0000
IEF196I IGD104I IBMUSER.CTRACE1 RETAINED,
IEF196I DDNAME=TRCOUT01
which gives me the name of the data set IBMUSER.CTRACE1.
Use IPCS to look at the trace
- option =0 to specify the name of the data set
- =6
- dropd
- The above command clears out any old information about the data set
- CTRACE COMP(SYSCEA) full
I had some data in the trace – but not for the problem I had…. so I need to try something else.
The advanced class.
You do not need to have a member in parmlib. You can use
TRACE CT,ON,COMP=SYSCEA
and do not specify a PARM. This will then prompt for the parameters, asid, jobname, writer and options.
ColinPaice 