sar and Solaris Zones
If you have a machine running zones, it is inefficient to setup sar in each of the zones. Just set it up in the global zone (I like 5 minute intervals) and then add /var/adm/sa as an lofs mount from the global zone to each of the local zones.
root@global # zonecfg -z webzone
add fs
set dir=/var/adm/sa
set special=/var/adm/sa
set type=lofs
add options ro
end
exit
root@global # zoneadm -z webzone reboot