I attended Drupal Summit in Genk a couple of days ago and amidst the general “Drupal is the best thing since sliced bread” atmosphere, there were some interesting discussions about the platform’s maturity. Especially the presentations of Peter Van Den Broeck (for VRT) and Wouter Mertens (for competitor VMMA) seemed to be on opposite sides, with VMMA having multiple successful Drupal-sites in production and VRT struggling to get their projects finished, telling Captain Buytaert “Dries, we’re not there yet“. But underneath the surface and despite the differences (a dedicated team of sysadmins & developers at VMMA vs fixed price, project-based external development for VRT), both were talking about the same problems on a technical level; modules & performance.
The Drupal module community is a great bunch of enthusiastic developers, building an impressive number of modules that cover almost any feature one would want to have in a website. But module quality, support & compatibility varies enormously. Some modules seem to be true Rube Goldberg machines, providing tons of functionality that only few people need but which makes the the UI a usability-hell and the code complex, error-prone and possibly a real performance-hog.
And while we’re on the subject; performance doesn’t come out of the box and Drupal as such does not scale very well. Install it with a bunch of modules, generate a reasonable amount of page requests and you have a CPU-intensive system that generates a crapload of database-connections. Adding memcache between your Drupal & MySQL helps, as most requests will be handled from cache. And putting a caching reverse proxy (Varnish, Squid or even Apache’s mod_proxy+mod_cache if you insist) in front of your Drupal does miracles, serving visitors the same content without the need for Drupal to bootstrap. So sure, you can build a scalable solution that provides great performance, but one could say this is despite Drupal, not because of it. After all, when using Memcache & Varnish almost any CMS will have great performance, won’t it?
So yeah, Drupal can be a nice solution to your problem, but it does require more than just a superficial knowledge of how to install it together with some modules and a theme. Make sure there are smart people on your team or project, that have a profound knowledge of modules & module development and who know a lot about MySQL (and clustering, mirroring or master/slave setups), Memcache and Varnish (or Squid, forget about mod_cache if you can). You’re bound to run into some problems, as Peter Van Den Broeck confirmed, but with the right people and architecture your Drupal-project can indeed be the best thing since sliced bread.