Chris Denman wrote:
I made a utility for Twitter that went viral for a week - my server took 30,000 hits in a few hours. Of course, it crashed. I went away and tried everything to get it working under this sort of load. Thing is, the traffic slowed and I'll never know if my new setup with hold up. Can I expect, say, 200 concurrent users on a Embperl website with only 1Mb of Ram? If so, what's the best Apache configuration?
Does every single request need to be handled by Embperl, or could you perhaps cache some of the pages? I use a two level caching reverse proxy Apache configuration on my server. There are basically two installations of Apache - one with mod_proxy, which serves all static content (images mostly). It passes all requests for dynamic content to the "backend" Apache process (running on the same server) which has mod_perl and embperl. The front end apache can be very lightweight, as it doesn't have mod_perl etc it doesn't use much memory, and so you can have a whole bunch of them running. And if you use mod_cache, then you can also cache the results that come from the backend embperl server. So that means that if you're careful about setting expiration times for your embperl content, then you can substantially lighten the load, and still be able to handle a whole bunch of concurrent users without breaking a sweat.
You usually find that not every single "dynamic" page actually has to be generated anew for every single request. For example, on my community website, there are pages which are "what's new" indexes of content. These are set to have a cache expiry of one minute. So if a whole bunch of people hit that page, most of those requests will be served by the front end, until that version expires (next minute). So the backend is only hit for that page once per minute. It gets a bit more complicated if you have users with cookies, but basically I only set 'no-cache' for those parts of the site that are definitely needing Embperl per-request (e.g. editing forms, user-specific areas etc).
Caching is how you handle scaling - most websites go down because they handle everything with the dynamic engine, and then one day they get hit by a bunch of people and "bang". Early on I had a couple of my articles go to the front page of slashdot. As soon as I put in the caching architecture, my server was able to handle slashdottings without breaking a sweat. I'd get upward of 40,000 hits within a few hours, and the server was just basically idling along, since most of the hits were effectively being served as static content from cache - even though the article was dynamically generated by embperl.
Can't wait for any new versions....!
Me too - I'm so glad to see Gerald back on the list. I have based my entire website development around Embperl (hundreds of thousands of lines of code now, and going on for ten years of development). I was afraid that Embperl was abandonware, since I'd seen the embperl list traffic dwindle and questions go unanswered. I really hope to see embperl rekindled. If/when my business takes off (of course it will, any day now!) then I hope to be able to send some appreciation Gerald's way.
Neil http://www.neilgunton.com/ --------------------------------------------------------------------- To unsubscribe, e-mail: embperl-unsubscr...@perl.apache.org For additional commands, e-mail: embperl-h...@perl.apache.org
