Re: Hardware recommendations to scale to silly load

Vivek Khera <khera(at)kcilink(dot)com> writes:

> The front-end small processes get to deal with your dialup customers
> trickling down the data since it buffers your backend for you.

Huh. Well, I used to think this. But I think I was wrong. I used to have
apache proxy servers running in front of the mod_perl apache servers. The
proxy servers handled image and static html requests, and proxied any dynamic
content to the mod_perl servers.

In fact most web pages are only a few kilobytes, and you can easily configure
the kernel buffers on the sockets to be 32kb or more. So the proxies would
only come into play when there was a really large dynamic document, something
that should probably never happen on a high volume web site anyways.

I think the main source of the benefit people see from this setup is the
static content. For that you get a bigger kick out of separating the static
content onto entirely separate servers, preferably something slim like thttpd
and just exposing the mod_perl/php/whatever servers directly.

The one thing I worry about exposing the dynamic servers directly is
susceptibility to dos or ddos attacks. Since all someone has to do to tie up
your precious heavyweight apache slot is make a connection, one machine could
easily tie up your whole web site. That would be a bit harder if you had
hundreds of slots available. Of course even so it's not hard.

--
greg