#The difference between the "web" and "application" layers are this:
#the "web" layer is simply the web server (without anything rails-
#specific) and the "application" layer is (for instance) the set of
#FCGI listeners. Using lighttpd (or getting clever with apache/
#haproxy) you can have multiple stand-alone FCGI listeners running on
#one machine, with the web server running on another machine and
#sending the requests to the listeners.
thanks Jamis. That gives me a clearer/more specific view.
i used to (naively) view it like this:
web [top]- web server stuff
app [mid]- stuff not of the above and not of below but controls them
db [bot]- db stuff
#You can use the spawn-fcgi utility (it comes with lighttpd, but it
#isn't lighttpd-specific) to launch new FastCGI listeners. To make
#things simple, you can use the spinner and spawner utilities that
#come with Rails (and which wrap the spawn-fcgi utility). Check out
#the SwitchTower manual for info on how to use these.
great you mention lighttpd. I'm having difficulty getting it thru debian's apt. Seems like debian people are not interested in lighttpd 
#As for configuring lighttpd and apache to communicate with
#independently spawned fastcgi listeners, you'll need to check out the
#docs for those.
···
Jamis Buck [mailto:jamis@37signals.com] wrote:
#
#It definitely isn't as simple configuring a setup like this as it is
#to just let the web server manage the listeners, but it scales much
#further. That said--don't try scaling before you need it. Keep things
#as simple as possible, for as long as possible, and you'll save
#yourself a lot of grief in the long run.
#
great advice.
Thanks much and kind regards -botp
#- Jamis
#