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From Joe Lewis <>
Subject Re: what should be done in a vhost_db module?
Date Mon, 07 Apr 2008 20:58:02 GMT
ed wrote:
> On Mon, 07 Apr 2008 10:12:18 +0200
> Robert Schulze <> wrote:
>>> Are you doing this to save memory?   
>> This is one important fact - it saves a huge amount of memory with 
>> several thousands of virtualhosts.
>> One more interesting thing is, that apache does not need to be
>> restarted when adding domains :-)
> Apache doesn't have to be restarted when adding virtual domains, you
> can add the domains to the conf and send a USR1 to httpd and it will
> reload that without interrupting existing requests AFAIK.

I've watched this thread with some interest, and some chuckling.  There 
are two distinct perspectives here, and I just thought I'd tackle both 

2 - some of us think that whatever Apache needs will be configured 
somewhere when apache loads, or we will create new virtual hosts on the 
fly.  This is an EXCELLENT suggestion when it comes to minor changes 
over a longer period of time.

1 - the original poster is probably doing what I have done, which is 
called a mass virtual host - there is no server record for each host, as 
there could be (literally) thousands of virtual hosts, many being 
created every minute, and also deleted.  These kinds of environments are 
typically found in web hosting companies or ISP's - a service geared to 
handle harsh dynamics.  Often, there is no other way to implement a 
hosting service in this situation than this form.

In Apache 2.0, there was a mass_virtual_host module.  In Apache 2.2, 
there is actually a mod_vhost_alias module - these modules simply 
overwrite some settings without creating new server_rec structures, such 
as setting the r->hostname (hostname on a per-request basis, using 
r->pool), a simple mapping method to a directory for the "document 
root", and some other pieces to ensure environment variables and tables 
are set for things like PHP and CGI.  They run quickly, and are designed 
for high volumes and high numbers of sites.

For the original poster, I suggest reviewing mod_vhost_alias.c in the 
apache source code modules/mappers/ directory - it should give you a 
great concept of what must be done to mimmick a configured server_rec 
without actually creating one.

Joseph Lewis <>
"Divide the fire, and you will sooner put it out." - Publius Syrus

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