Collecting System Activity Data Automatically (sar)

Three commands are involved in automatic system activity data collection: sadc, sa1, and sa2.

The sadc data collection utility periodically collects data on system activity and saves it in a file in binary format--one file for each 24-hour period. You can set up sadc to run periodically (usually once each hour), and whenever the system boots to multiuser mode. The data files are placed in the directory /usr/adm/sa. Each file is named sadd, where dd is the current date. The format of the command is as follows:

/usr/lib/sa/sadc [t n] [ofile]

The command samples n times with an interval of t seconds (t should be greater than 5 seconds) between samples. It then writes, in binary format, to the file ofile, or to standard output. If t and n are omitted, a special file is written once.

Running sadc When Booting

The sadc command should be run at system boot time in order to record the statistics from when the counters are reset to zero. To make sure that sadc is run at boot time, the /etc/init.d/perf file must contain a command line that writes a record to the daily data file.

The command entry has the following format:

su sys -c "/usr/lib/sa/sadc /usr/adm/sa/sa`date +5d`"
 

Running sadc Periodically With sa1

To generate periodic records, you need to run sadc regularly. The simplest way to do this is by putting a line into the /var/spool/cron/sys file, which calls the shell script, sa1. This script invokes sadc and writes to the daily data files, /var/adm/sa/sadd. It has the following format:

/usr/lib/sa/sa1 [t n]

The arguments t and n cause records to be written n times at an interval of t seconds. If these arguments are omitted, the records are written only one time.

Producing Reports With sa2

Another shell script, sa2, produces reports rather than binary data files. The sa2 command invokes the sar command and writes the ASCII output to a report file.