from...
http://www.pluzzi.com/pluzzi/os/solaris8.html
SAR
To enable the SAR subsystem to function on solaris, you need to enable
its daemons and data collectors.
cd to /etc/init.d
vi perf, and remove the comments
cd /etc/rc2.d or some other directory that is used for your run-level startup, and see that there is a file that is linked to /etc/init.d/perf.
Mine was /etc/rc2.d/S21perf.
run that file, to be sure all is ok, so "/etc/rc2.d/S21perf start"
run the "sar -A" command, to be sure it is working.
crontab -e sys ----> to uncomment the lines for sar.
Thats it !!!