AIX 5L Problem Determination - IBM Redbooks

9.5.2 Starting a trace
9.5.3 Trace reports
A trace can be started in background mode or interactive mode.
The usual way to perform a trace is in the background using the -a flag. An
ampersand (&) is not necessary at the end of the command, as the trace
command will spawn the trace daemon and return to the shell prompt
immediately. The trace is stopped using the trcstop command.
To perform a trace in interactive mode, invoke the trace command with a list of
events you want to monitor and the name of the trace log output file. The events
are assigned numbers that are called trace hooks.
A typical command sequence may be as follows:
# trace -a -j 15b
# myprogram
# trcstop
This example traces only the open operating system that is made on the system.
Trace uses in-memory buffers to save the trace data. There are three methods of
using the trace buffers:
Alternate mode This is the default mode. All trace events will be recorded
in the trace log file.
Circular mode The trace events wrap within the in-memory buffers and
are not captured in the trace log file until the trace data
collection is stopped.
Single mode The collection of trace events stops when the in-memory
trace buffer fills up and the contents of the buffer are
captured in the trace log file.
The binary /var/adm/ras/trcfile trace file contains all system events collected
during the trace period. To obtain a readable format, this file needs to be
translated using the trcrpt command, which generates an output report.
To write a formatted trace report to the /tmp/trace.out file, run the following
command:
# trcrpt -o /tmp/trace.out
The output of the trace report file is usually very large, depending on the trace
parameters and the system activity. Despite selecting a narrow time period for
Chapter 9. System access and printer problem determination 213