Sar understanding

[Loic Dachary]

   I'm using sar extensivly for two purposes : 


     - Writing a course chapter on Un*x tunning and tools to watch
       system activity (sar, sag, sadp)
     - Try to prove that GNU-emacs is not overloading our V*X-750 running
       N*XI V.2 (hopeless ?)
       

   The lack of documentation is partialy compensed by M.J.BACH famous book
and the AT&T 386/V.3 Administrator Guide. 
   But some points are still missing :

     sar -d : . Is there any ceil values for these data ? Specially
                %busy, r+w/s, avwait. I know for example that runq-sz
                should not be greater than 2, and %rcache lower than 90%.
              . Can blk/s be recalculated (approximately) with other values ?
                I tried to sum bread and bwrite without great success 
		(bread + bwrite <= blks/s / 2, could that mean bread is
		1024 byte blocks and blks/s 512 byte blocks ?)
     sar -q : . swpq-sz and swpocc have no values most of the time. But
                when the system is heavy loaded some values like 1.2 and 10%
                appear. I guess this is swapping ;-). But what hell does that
 		mean in a paged system ?
     sar -p : . The most stupid question due to my ignorance : what is a
                reclaimed page ? (rclm/s).
     

  Finally I'm interested in any idea or pointer about
     
     . Typical methods of diagnostics using sar.
     . Useful data mixin using sag (-y 'runq-sz 0 8 ; freemem 50 3000' for
       instance and specially some using -x 'everything but time')
     . Public domain system activity tools


  Thank you, all.