[lug] [OT] Apache 1.3 vs. 2.0 on Linux

[rm at fabula.de]

On Fri, Apr 30, 2004 at 04:58:02PM -0400, Michael D. Hirsch wrote:
> On Friday 30 April 2004 03:03 pm, rm at fabula.de wrote:
> >
> > ??? Are you saying that apache doesn't increase the number of processes
> > when i runs out of available ones? That's certainly not true. You can
> > set the number of minimum processes as well as the number of maximum
> > processes (very important!) and the max number of _idle_ processes.
> > Our webserver has a minimum count as low as 15 but does fork up to
> > 1000 servers during peak hours (one needs to tweak/patch the kernel
> > to be able to use such high process counts ...).
> 
> Really.  I've been wrong, before, too.  :-)  I guess I misunderstood some of 
> the advantages of 2.0, then.  Threads are still a bit lighter weight than 
> processes (especially in kernel 2.6.x), but that is a lesser advantage.
> 
> Do you know how apache distributes its processes, then?  Since each forked 
> process is actually a sparate process, how do they communicate that they are 
> all busy?  Is it using IPC, or something else?

There's the 'scoreboard file' -- basically a shared memory structure where
each client puts it's state (idle,running ...). Modules such as the server
status module use can show this information. The controlling server will
check the scoreboard to start or kill children according to the settings in
the configuration file.

 HTH RalfD

> Michael
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