Setting Up Automatic Data Collection (sar) (System Administration Guide: Advanced Administration)

System Administration Guide: Advanced Administration

Setting Up Automatic Data Collection (`sar`)

The sar command can be used either to gather system activity data itself or to report what has been collected in the daily activity files that are created by the sadc command.

The sar command has the following formats:

sar [-aAbcdgkmpqruvwy] [-o file] t [n]

sar [-aAbcdgkmpqruvwy] [-s time] [-e time] [-i sec] [-f file]

The following sar command samples cumulative activity counters in the operating system every t seconds, n times. The t should be five seconds or greater. Otherwise, the command itself might affect the sample. You must specify a time interval in which to take the samples. Otherwise, the command operates according to the second format. The default value of n is 1. The following example takes two samples separated by 10 seconds. If the -o option were specified, samples are saved in binary format.

$ sar -u 10 2

Other important information about the sar command includes the following:

With no sampling interval or number of samples specified, the sar command extracts data from a previously recorded file. This file is either the file specified by the -f option or, by default, the standard daily activity file, /var/adm/sa/sadd, for the most recent day.
The -s and -e options define the starting time and the ending time for the report. Starting and ending times are of the form hh[:mm[:ss]], where hh, mm, and ss represent hours, minutes, and seconds.
The -i option specifies, in seconds, the intervals between record selection. If the -i option is not included, all intervals that are found in the daily activity file are reported.

The following table lists the sar options and their actions.

Table 13–2 Options for the sar Command


Option	Actions
`-a`	Checks file access operations
`-b`	Checks buffer activity
`-c`	Checks system calls
`-d`	Checks activity for each block device
`-g`	Checks page-out and memory freeing
`-k`	Checks kernel memory allocation
`-m`	Checks interprocess communication
`-nv`	Checks system table status
`-p`	Checks swap and dispatch activity
`-q`	Checks queue activity
`-r`	Checks unused memory
`-u`	Checks CPU utilization
`-w`	Checks swapping and switching volume
`-y`	Checks terminal activity
`-A`	Reports overall system performance, which is the same as entering all options.

Using no option is equivalent to calling the sar command with the -u option.