Hey, it's me, avogadr.io guy. The first thing to give out seemed to be the molecule rendering server Sourire (running locally) which is a Clojure webserver wrapper around a cheminformatics toolkit (see GitHub for more info). The molecule rendering server process was crashing for some reason under the load (physical memory, disk space, jury's still out I'm honestly not sure at this point) so the site itself was being served but any requests to Sourire were failing (hence the lack of a molecule in the UI during the hug of death). More RAM/disk space seems to have sorted it out for now and it's holding steady. I guess it comes down to a question of how many molecule renders are possible concurrently on the hardware (including any temp file/cache/RAM cleanup time).

I'm sure you've thought about moving the renderer clientside in JS - what's blocking it? Have you played with ClojureScript before?

It's certainly crossed my mind, and it'd be great to implement something like that, but the Clojure is just a wrapper around a large and complicated cheminformatics toolkit. Porting the actual rendering library (Java/C++?) would probably be a substantial undertaking.

If it's pure java, it's possible to compile using GWT to JavaScript for use on the client side.

If it's C++, then emscripten might be a possible choice.

If it's a mixture, then that's a much harder problem...

It's probably a hard one:

https://github.com/cryos/avogadro/

Mostly C++, then the clojure wrappers in java? There do exist pure javascript molecule drawers, though.

Great work :) Je souris aussi

I'm curious as to what type of hardware these sites that can't handle HN traffic are running on? I've had a project go front page before, and it was nothing a $10 droplet couldn't handle. A few hundred concurrent users is nothing for a webserver/database.

It also depends on what one runs on it. This website seems to dynamically generate images (3D, maybe?), and send them to clients.

I'll give to this one in particular, but blogs have had the same effect. It's bizarre when commodity hardware is so powerful these days.

It's a 2D monochromatic PNG of the chemical drawing. The body's style links to the background image URL like 'https://www.avogadr.io/api/name/1440/900/38ce5d/caffeine' or 'https://www.avogadr.io/api/name/1440/900/38ce5d/LSD'.

Does making a chemical drawing usually take that much time?

Just because people know how to write for a blog doesn't mean they know how to scale a web server.

I had 10000 concurrent users on a front page blog post once. I think time of day had a big effect.

What day/time did you achieve 10,000 concurrent?