Re: [cobalt-users] httpd configuration on RaQ/RaQ2/RaQ3

["Brian Busche" <brian@xxxxxxxxxxxxx>]

I am currently running a RAQ2 with the default httpd.conf settings and I
having frequent CPU load warnings.  I traced this to a virtual site that run
some heavy CGI cripts that are being hit 5-10 times per minute or more.  The
256 meg of RAM seems to be enough, with average memory usage aound 220 megs.
The CPU just gets swamped however an d I am curious if the SpareServer
settings would have any affect.

I can not get a telnet connection when things are really bad, so I do not
know the number of processes running during a CPU warning.  Typically when I
can telnet to the RAQ,  I see over 100 processes, over 80 sleeping, 7 or
more running, and occasionally 1 zombie process.

The ratio of sleeping to running proceses seems excessive at 10:1

Can this be dealt with via httpd.conf?   should I be considering a RAQ3? or
perhaps a Cray Supercomputer : )   ???

Brian Busche
brian@xxxxxxxxxxxxx



----- Original Message -----
From: Duncan Laurie <duncan@xxxxxxxxxx>
To: <cobalt-users@xxxxxxxxxxxxxxx>
Sent: Wednesday, February 09, 2000 5:35 PM
Subject: Re: [cobalt-users] httpd configuration on RaQ/RaQ2/RaQ3


> "Drew T. Nichols #333" wrote:
> >
> > Question for everyone...
> > I've been running Apache for 5 years now but never really "thought"
about it
> > and performance issues...  A friend of mine was looking at httpd.conf
and saw
> > the StartServers and Max/Min SpareServers values on the RaQ2 and
laughed.
> >
> > Seems that Netscape connects to 4 "servers" at one time.  So my friend
> > recommends 60 start servers, or 15 simulataneous users.  Any comments on
> > this?  The Cobalt out of the box value is 5.
> >
> > Regards,
> > Drew
>
>
> The StartServers directive determines only how many server child processes
are
> started when the web server is initially brought up.  It has no bearing on
how
> many simultaneous connections can be handled; for that see the MaxClients
> directive (default is 150).
>
> If you set the StartServers at 60, and restart your web server you will
run out
> of memory fast...  on raq2 figure 6MB virtual memory usage (~1MB resident)
per
> httpd process * 60 is 360MB total usage (or 60MB resident).  Those numbers
are
> higher for raq3 or any SSL enabled web server, and even higher if you add
in
> things like mod_php or mod_perl.
>
> The {Min,Max}SpareServers directives define a pool of server child
processes to
> handle requests.  The desired effect is to reduce the initial cost of
creating
> child processes when a new connection is established--and hopefully reduce
the
> startup time for web sites.
>
> This is where you should focus performance tweaking.  You might set
> MaxSpareServers higher so that in high-traffic time periods there will be
> plenty of extra child processes sitting around (not currently serving any
> requests), but they will eventually be killed off by the parent if the
traffic
> dies down.  Tweaking the MinSpareServers value will define a minimum
number of
> spare child processes at any one time--apache will never let the number of
idle
> child processes slip below this value.
>
>
> -duncan
>
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