I know Websense does pretty much the same thing as Blue Coat in "pre scanning" sites. The best solution is to use css compression/aggregation (in D5+) and javascript compression/aggregation (D6) to reduce requests. Those are some of the files these services latch onto, and when they read the entire site they won't cache the files, but rather reread them on every page request.This will help keep the cpu usage down since Apache won't have to keep spawning connections for the files.
Also any kind of caching you can get in there. There are some scenarios and modules it won't work with. For example - if your Drupal install is in a subfolder of the web root. One way to fix that is to put Drupal on its own subdomain. Also trying op-code level caching like APC is a big plus (generally a 20%+ increase). Another option is using something like cacherouter with memcache and then enabling the page caching through that. With apc+cache router+memcache, I can pump out over 200 requests per second on an old dual-core AMD server and my load never goes above 60 using D6.
Of course if you are on shared hosting getting these things setup can be very difficult, if not impossible (APC and Memcache require a system admin to install and configure the modules). I would then look at going to a managed VPS (if you aren't comfortable handling your own system admin). Companies like wired tree have these services starting at around $40 (us) a month.
Jamie Holly
Daniel Carrera wrote:
Ok, I have a little more information:
All the schools in Kent county, UK (pop 1.4 mil) go through the same IP address. So that's may thousand PCs. Most schools "have an ISA server on site running Websense". Websense appears to be some sort of gateway software, and I imagine that ISA is the Microsoft "Internet Security and Acceleration" Server. I have no idea if either of these products has the problems of Blue Coat.
Daniel.
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