mod_proxy with light and heavy httpd - questions

[John ORourke <suppressed>]

Hi folks, I'm just implementing the usual light/heavy httpd setup with
mod_proxy and mod_cache and have a couple of queries.

The setup is simple - port 80 is my light httpd, serving static and
nearly static content, using mod_cache and mod_proxy to send some
requests to the heavy mod_perl engine on another port.

1. I was initially put off mod_proxy by the docs (
http://perl.apache.org/docs/1.0/guide/strategy.html#Apache_s_mod_proxy )
that say mod_proxy has a "difficult case is where you have DNS aliases
that map to the same IP address".  I then found the ProxyPreserveHost
directive which preserves the HTTP Host header when passing the request
on - am I right in thinking the docs need to be corrected, and this is
no longer an issue?

2. I use mod_gzip for inline compression.  Should I put mod_gzip in the
heavy or the light httpd?  I'm thinking that if heavy httpd compresses
it, mod_cache will have less to store and won't have to re-compress.
However maybe light httpd should be doing the actual compression work,
freeing up heavy for more requests.  Any recommendations?

cheers
John