Apache2 troubleshooting

[Fred]

On Friday 27 October 2006 11:27, Ben Scott uttered thusly:
> On 10/27/06, Fred <puissante at lrc.puissante.com> wrote:
> > Then you can use your browser and do
> > "http://yourdomain.com/server-status" to see how active your server
> > really is.
>
>   Or combine that with the nifty "watch" command I just learned about
> (in this forum) recently:
>
> watch "elinks -dump http://yourdomain.com/server-status"
>
> (Replace "elinks" with "lynx" if that's what you have.)
>
> -- Ben

Oh, that's a cool command. Saves me from having to do:

for ((;;)) do clear; lynx -dump http://yourdomain.com/server-status; sleep 
15; done

Just a note on server-status: If you, in your browser, do:

http://yourdomain.com/server-status?refresh=15

It will automatically refresh every 15 seconds. You, of course, can change 
that to whatever refresh rate you desire.

You may also do:

http://yourdomain.com/server-status?auto

Which will yeild a plain text format easily parsable by scripts, etc., which 
is how I get my web applications to monitor server loads and react 
accordingly. The output it produces is something like:

Total Accesses: 11874
Total kBytes: 218608
CPULoad: 13.3988
Uptime: 3899
ReqPerSec: 3.0454
BytesPerSec: 57413.3
BytesPerReq: 18852.5
BusyWorkers: 12
IdleWorkers: 17
Scoreboard: W_______K__K____.K_WK..._ ...

Of particular interest (to me) are the "BusyWorkers" and "IdleWorkers" 
fields, as these two fields are a direct reflection of server load, whose 
max values are determined by your Apache settings for Prefork or MPM. A good 
showing here is to see BusyWorkers low relative to your max settings and to 
have "IdleWorkers" be something other than 0. Server should be very 
responsive to human visitors at that point. A bad showing is 
when "BusyWorkers" is close to or at your max setting and "IdleWorkers" is 
0, in which case Apache simply can't handle any new queries in a timely 
fashion and visitors to your sites will wait 30 seconds or longer for 
resources to free up. Not Good.

I actually take an normalized exponential moving average of "BusyWorkers" 
and "IdleWorkers" and have my apps make decisions on that basis, so spike 
demands are smoothed out and the server does not react spasmodically to the 
ever shifting loads. 

Probably more than you wanted to know. :-)

-Fred