A 15 minute introduction to the Cassandra distributed data store from the February 2011 London Web meetup. This covers the basics of who is using it, why you might want to use it (due to the large amount of data being collected by Web Apps today) and, most importantly, _what_ it is!

1. An introduction to Cassandra London Web Meetup 20/1/2011 Dave Gardner @davegardnerisme

2. Plug Regular Cassandra meetup at Skills Matter near Old Street. Monday 21st February. Free beer! Free pizza! http://meetup.com/Cassandra-London

3. What is Cassandra?

4. Cassandra is a distributed, fault-tolerant, scalable, column-oriented data store More on this in a minute…

5. Who is using Cassandra?

7. Why might you want to use a distributed, fault-tolerant, scalable, column-oriented data store?

8. Collecting preferences

9. Recommendations The Tweeted Times

10. Social graphs

11. That’s a lot of nuts http://www.flickr.com/photos/swamibu/3520926105/sizes/o/

12. Why Cassandra?

13. Cassandra is a distributed, fault-tolerant, scalable, column-oriented data store

14. #1 #6 #2 No master node (no single point of failure) #3 #5 Client #4

15. Cassandra is a distributed, fault tolerant, scalable, column-oriented data store

16. Replication Factor = 3 #1 #6 #2 #3 #5 Client #4

17. Key feature! Cassandra hastunable consistency (on a per-request basis)

18. Consistency level: how many replicas must respond to declare success? Plus some DC aware levels

19. Cassandra is a distributed, fault-tolerant, scalable, column-oriented data store

20. Key feature! Scales linearly for both reads and writes (horizontally)

21. Cassandra is particularly suited to use-cases that have a high write load

22. Cassandra is a distributed, fault-tolerant, scalable, column-oriented data store

23. {‘foo’ => {‘bar’ => ‘baz’}} {key => {col_name => col_value}}

24. { column_family => { key => { col_name => col_value } } }

25. That was a very brief overview Learn more at Cassandra London!

26. Thank you! Any questions? Dave Gardner @davegardnerisme Cassandra London @cassandralondon http://meetup.com/Cassandra-London

27. Further reading for the keen ones… WTF is a SuperColumn? An Intro to the Cassandra Data Modelhttp://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model Clients list (Python, Java, .NET, Ruby, PHP)http://wiki.apache.org/cassandra/ClientOptions Cassandra docs on DataStax websitehttp://www.datastax.com/docs/0.7/index Introduction to Cassandra by Aaron Mortonhttp://www.slideshare.net/aaronmorton/well-railedcassandra24112010-5901169 Operations and troubleshooting guide by Ben Blackhttp://www.slideshare.net/benjaminblack/cassandra-summit-2010-operations-troubleshooting-intro

28. More reading for the really keen… Introduction to Cassandra: Replication and Consistency by Ben Blackhttp://www.slideshare.net/benjaminblack/introduction-to-cassandra-replication-and-consistency Running Cassandra on Amazon EC2 by Dave Gardnerhttp://www.slideshare.net/davegardnerisme/running-cassandra-on-amazon-ec2 4 Months With Cassandra, a love story by CloudKickhttps://www.cloudkick.com/blog/2010/mar/02/4_months_with_cassandra/ Cassandra London meetuphttp://meetup.com/Cassandra-London