Wednesday, January 02, 2008

Erlang for Five Nines Talk

Erlang for Five Nines Talk

I attended the above talk given at on the 13th December. There were 37 attendees, two of which were women (women in technology take note.) I'm afraid I was virtually the only suit in the room apart from Francesco (the speaker) so I stuck out like the proverbial sore thumb.

It was a good talk, well received and well presented. Not particulary technical, so I'm afraid I may have asked too many questions, but I couldn't let the opportunity to get a real understanding of practical Erlang slip by. I was particularly interesting in support for multicast but as no one else had heard of it I kept quiet.

Shared Memory Support

One area I was particulary interested in was
no shared memory support - all comms has to go through a tcp/ip software stack apparently. I can understand the aesthetic reasons behind this but the implications for high performance messaging are significant: from one Erlang process to another on a remote machine there's an extra two stacks to cross. It would be interesting to compare with the high performance messaging providers.

Real-world Erlang - Yaws Performance

One rather amusing piece was on the performance of Yaws, the Erlang web server, which shows very high throughput compared to Apache. Yaws manages to run 80,000 parallel sessions, serviing 2 x 20KB pages whilst poor old Apache dies after 4,000.

One unfortunate side effect of this would be to consume your organisation's entire bandwidth so I'll stick with Apache for now. If I want to ship that much (presumably) random data, the last tech I'll use is a web server. HDF5, Lustre, GFS, Gigaspaces all have a better handle on this sort of data architecture.


I like Erlang as a concept but they have a mountain to climb with OTP (the function library) if they're going to be more than niche. New features are being added all the time - the latest being a "posix like" threading library and support for SMP. Faster ASN.1 support too with the latest version. Erlang is growing up fast.

For those of you interested in learning Erlang, I'd recommend starting with Joe Armstrong's PhD.