You can use either of the following interfaces to extract data
from the SMF log stream:
- IFASMFDL, which is the SMF dump utility
- IFASEXIT, which is the SMF Logstream Subsystem Exit
With IFASMFDL, you can dump the data from one or more specified
log streams into one or more data sets. For detailed information,
see Dumping SMF log streams - IFASMFDL.
Using IFASEXIT, you can obtain records from one SMF logstream at
a time. IFASEXIT is executed as a logstream exit routine that is invoked
in JCL using the SUBSYS DD statement parameter.
Figure 1 shows the syntax of this statement.
Figure 1. Syntax
of SUBSYS JCL for IFASEXIT //ddname DD DSNAME=log.stream.name,
// SUBSYS=(LOGR,IFASEXIT[,'SUBSYS-options1']
// [,'SUBSYS-options2'])
- log.stream.name
- Specifies the name of the log stream to read. The name can be
1 to 26 characters in a data-set-name format.
- SUBSYS-options1
- Specifies options that are meaningful to all exit routines. For
detailed information, see "JCL for the
LOGR Subsystem" in z/OS MVS Programming: Assembler Services Guide.
- SUBSYS-options2
- Specifies unique exit routine options. For IFASEXIT, the following
parameters are accepted:
- SID(xxxx)
- This is an optional parameter used to indicate that only records
written by the operating system with the specified system identifier
are to be written to the output data set. The xxxx value
indicates the system identifier and can be 1 to 4 alphameric characters.
There is no default value. Only one SID parameter can be specified
for each invocation of IFASEXIT. If SID is not specified, records
pertaining to all SIDs found in the logstream are written.
- SMEP(hhmm)
- This is an optional parameter used to designate a "smart end
point" value. The smart end point value, specified as hhmm,
results in a calculated time that designates when to discontinue browsing
the SMF logstream. By default, if this parameter is not specified,
IFASEXIT reads records all the way to the end of the logstream before
completing. However, by specifying a Smart End Point value, you can
choose to stop reading logstream data at a designated point before
the actual end of the logstream. This can shorten the IFASEXIT processing
time.
The hhmm value describes the number of
hours and minutes to use to calculate the smart end point. The total
value cannot exceed 2 hours (designated as 0200).
- hh
- A number between 00–02
- mm
- When hh is less than 2, this is a number between
00–59; when hh is 2, the mm value
must be 00.
The smart end point value is calculated by adding
the value specified by hhmm to the time specified
in the TO=ending-time value
of the SUBSYS-options1 parameter. The smart end
point is satisfied when it has been determined that records for all
known SIDs, or records for only the SID specified with the SID(xxxx)
parameter, contain a date and time that is past the calculated smart
end point.
Note: It is possible that data is buffered on a z/OS® image, and writes to this
logstream are delayed. In this case, IFASEXIT may not dynamically
detect the image that was buffering data, and may assign a smart end
point that is actually prior to when some of these records were actually
written ("hardened") to the logstream. These records would remain
un-selected for output, and would be candidates for selection on the
subsequent run of the job that invokes the IFASEXIT exit.
If
the following
SUBSYS-options1 parameters are specified,
the SMEP parameter is not allowed