The journey so far...

Historical note: This post written under the previous blog name ‘Diary of a Distributed Virgin’

Funnily enough, I didn’t wake up one day and decide that I needed to learn about distributed systems. I did wake up one day (Tuesday to be precise) and decide to blog about the process, but that’s another thing entirely - in fact it came to me whilst cycling home from work. I like cycling.

So there was a start, but the start was vague. I’ll try to explain…

In the beginning there was a developer (me), and I’d worked on systems that Ithought had to really scale: I thought that capacity meant 2000 active users, and that high transaction rates meant 20 requests per second and I thought that scaling meant running on 2 machines with shared session state and a shared DB.

Then I moved to Betfair, and discovered 10000 active users, 100 tps and 10s of servers with distributed caches and a shared DB.

And then Werner Vogels came to visit and described Amazon: millions of users, thousands of servers, SOA, the cloud and no sign of a shared DB. And at the time, this sounded cool, but not only out of reach, just a bit excessive for the developer’s needs.

Around the same time, I started work on an integration of an external vendor to deliver games to Betfair’s customers. During that time I started to talk to Dan Creswell, and he introduced concepts such as service lookup and thinking about failure. So we stumbled through, built a bunch of services, thought a bit more about what we were doing, and how we were doing it, and why we were doing it that way. To cut a long story short, the project was a success, both from a technology perspective and from a business perspective.

And from a personal perspective - I’d seen there can be another way… Alright, our services still talked to a single shared DB, but there were noticeable improvements: * Multiple nodes in different datacentres, all active at the same time * Clients finding services without using static configuration * Clients expected failure and dealt with it * We’d tested for failure

So, project over, I moved to another team. As is often the case, you join a new team and think how much better you could have written the system if you started now. Reverting to type, off we go looking for a framework… enter grid computing. I’ll leave the detail for another post, but suffice to say, there was the silver bullet - and then realized it wasn’t. It was good, well suited to some problems in the online gaming world, but I didn’t fully understand the fundamentals to understand the explanation from colleagues. I read about Erlang, played with it briefly, but knew that there was no way a company would base a major part of it’s product suite on such an obscure language.

Around the same time, I read this blog posting from Werner and set out to find that reading list and get going on understanding those fundamentals…