Acunu

"For BGT, we were planning for peak voting loads of 10,000 votes/second. Our main database runs on MySQL using the Amazon Relational Database Service. Early testing showed there was no way we could hit that level using RDS – we were maxing out at around 300 votes/s on an m1.large database instance. Even though there are larger instances, they’re not 30x bigger, so we knew we needed to do something different.

...

We wired Cassandra into our stack, and started load testing against a 2-node Cassandra cluster. While we’d originally expected to need more nodes, we found that the cluster was easily able to absorb the load we were testing with, thanks to the optimisations in the Acunu stack.

So how did it all go? Things were tense as the first show was broadcast and we saw the load starting to ramp up, but the Acunu cluster worked flawlessly. As we came towards the start of the live shows, we were totally comfortable that it was all working well.

Then AWS told us that the server hosting one of the Cassandra instances was degraded and might die at any point. Just before the first live finals."