January 24th, 2013


David Gardner: PHP Developer at Hailo


What does Hailo do?

Hailo is the taxi app. Hail a licensed taxi from your smartphone in two taps. Hailo currently operates in London, Dublin, Toronto, Boston and Chicago with more launching imminently.


How are you using Cassandra?

Cassandra is our primary storage engine for building globally distributed, resilient services. We currently use it to store customer records, traffic events, SMS and emails history and detailed job history. More use cases are being added all the time.


What made you choose it?

We chose it primarily due to Cassandra’s solid design principles that lead to a good high availability characteristic. Other key features for us include the flexibility it affords developers (tunable consistency) and how easy it is to go multi DC.


What tips do you have for someone getting started with C*?

I think it’s important to immerse yourself in theory behind Cassandra. Brush up on Dynamo and Big Table. This doesn’t take long and it gives a good understanding of why Cassandra does what it does. Beyond that, do lots of testing; get comfortable with your data model and how it reacts in your particular use case (do your own load testing).


Are you running C* in the cloud or your own DC?

We run on AWS with two global production clusters that both have nodes in six amazon AZs in two regions. We are currently looking at adding a third in preparation for our Tokyo launch.


Be sure to register for the 15th Big Data London event; David Gardner will be presenting Hailo’s C* use case.