I'm building an online service. I expect that this may have to scale to tens of thousands of users. For the sake of having a drop dead simple deployment. I decided to build the website front end on top of Drupal (the service itself is linked to from the site, but is actually delivered by node.js and thus wasn't part of this particular test).
I have had all kinds of fun in the past with PHP/MySQL and even Drupal vulnerabilities, so I decided to sign the site up for regular security scanning. The scanner just fired up for the first time and when it was complete my site had essentially become non-responsive. (Strangely the security scanner marked the site as having passed though) Logging in via SSH showed quite literally hundreds and hundreds of <defunct> apache processes. I'm guessing that they were stress testing the site and obviously the site fell down. What bothers me is that there were hundreds of apache processes just sitting there dead. Since the box is only a single core with the ability to use up to 2 in a burst type situation (Amazon EC2 t1.micro to be exact). I don't really see the advantage of spinning up a whole new process just to deal with a new connection. Seems like death by a thousand paper cuts to me. I'm aware that node spins a new thread but not a new process. I would think that apache would have a mode to do that as well. Is there any advantage to 1 process per connection? Is there possibly a better configuration I could try that would allow it handle the load better? I'm aware that if the website is going to be under regular heavy load that there are some really important steps I can take such as serving static content from a CDN, putting the site behind an autoscaling load balancer etc. Those are in the works, but before I do all of that I want to make sure I have the best apache config I can considering the hardware limitations. This way we only scale once we've made the most effective use of hardware. FYI the server is running Ubuntu 12.04 with all the latest updates applied. Apache config is stock I'm even serving content right out of /var/www. Same with PHP. The DB server is on it's own seperate instance and is MySQL 5.6 managed by Amazon Simple RDS. Thanks in advance! /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
