Introduction to Apache Cassandra

1 . Introduction to Apache Cassandra™ Patrick McFadin VP Developer Relations, DataStax @PatrickMcFadin 1 

2 . Cloud Applications 2 

3 . You may consider one of these …or one of these 3 

4 . “The definition of bad insanity engineering is doing the same thing over and over and expecting a different result” –Who knows 4 

5 . Sharding shard 1 shard 2 shard 3 shard 4 App Server client 5 

6 . Sharding Customer Name A-F G-M N-T U-Z App Server client 6 

7 . 2005 - It's broke! 7 

8 . June 29, 2007 8 

9 . Dynamo Paper(2007) • How do we build a data store that is: – Reliable – Performant – “Always On” • Nothing new and shiny • 24 papers cited Evolutionary. Real. Computer Science Also the basis for Riak and Voldemort 9 

10 . BigTable(2006) • Richer data model • 1 key. Lots of values • Fast sequential access • 38 Papers cited 10 

11 . Cassandra(2008) • Distributed features of Dynamo • Data Model and storage from BigTable • February 17, 2010 it graduated to a top-level Apache project 11 

12 . Basic Architecture 12 

13 . Node Server 13 

14 . Token Server •Each partition is a 64 bit value •Consistent hash between -263 to +263-1 •Each node owns a range of those Token Range values 0 … •The token is the beginning of that range to the next node’s token value Data •Virtual Nodes break these down further 14 

15 . Server The cluster Token Range 0-100 0 0-100 15 

16 . Server The cluster Token Range 0-50 0 0-50 51 51-100 Server 51-100 16 

17 . Server The cluster Token Range 0-25 0 0-25 Server Server 26 26-50 51 51-75 76 76-100 51-75 26-50 Server 76-100 17 

18 . Replication DC1 10.0.0.1 10.0.0.1 00-25 10.0.0.4 10.0.0.2 76-100 26-50 10.0.0.3 DC1: RF=1 51-75 Node Primary 10.0.0.1 00-25 10.0.0.2 26-50 10.0.0.3 51-75 10.0.0.4 76-100 18 

19 . Replication DC1 10.0.0.1 00-25 76-100 10.0.0.4 10.0.0.2 76-100 26-50 51-75 00-25 10.0.0.3 DC1: RF=2 51-75 26-50 Node Primary Replica 10.0.0.1 00-25 76-100 10.0.0.2 26-50 00-25 10.0.0.3 51-75 26-50 10.0.0.4 76-100 51-75 19 

20 . Replication DC1 10.0.0.1 00-25 76-100 51-75 10.0.0.4 10.0.0.2 76-100 26-50 51-75 00-25 26-50 76-100 10.0.0.3 DC1: RF=3 51-75 26-50 00-25 Node Primary Replica Replica 10.0.0.1 00-25 76-100 51-75 10.0.0.2 26-50 00-25 76-100 10.0.0.3 51-75 26-50 00-25 10.0.0.4 76-100 51-75 26-50 20 

21 . Consistency DC1 Client 10.0.0.1 00-25 76-100 51-75 Write to partition 15 10.0.0.4 10.0.0.2 76-100 26-50 51-75 00-25 26-50 76-100 10.0.0.3 DC1: RF=3 51-75 26-50 00-25 Node Primary Replica Replica 10.0.0.1 00-25 76-100 51-75 10.0.0.2 26-50 00-25 76-100 10.0.0.3 51-75 26-50 00-25 10.0.0.4 76-100 51-75 26-50 21 

22 . Consistency level Consistency Level Number of Nodes Acknowledged One One replica acknowledges read One replica commits write Quorum 51% nodes agree on read or commit write Local Quorum 51% in local DC 22 

23 . Consistency DC1 Client 10.0.0.1 00-25 76-100 51-75 Write to partition 15 CL= One 10.0.0.4 10.0.0.2 76-100 26-50 51-75 00-25 26-50 76-100 10.0.0.3 DC1: RF=3 51-75 26-50 00-25 Node Primary Replica Replica 10.0.0.1 00-25 76-100 51-75 10.0.0.2 26-50 00-25 76-100 10.0.0.3 51-75 26-50 00-25 10.0.0.4 76-100 51-75 26-50 23 

24 . Consistency DC1 Client 10.0.0.1 00-25 76-100 51-75 Write to partition 15 CL= One 10.0.0.4 10.0.0.2 76-100 26-50 51-75 00-25 26-50 76-100 10.0.0.3 DC1: RF=3 51-75 26-50 00-25 Node Primary Replica Replica 10.0.0.1 00-25 76-100 51-75 10.0.0.2 26-50 00-25 76-100 10.0.0.3 51-75 26-50 00-25 10.0.0.4 76-100 51-75 26-50 24 

25 . Consistency DC1 Client 10.0.0.1 00-25 76-100 51-75 Write to partition 15 CL= Quorum 10.0.0.4 10.0.0.2 76-100 26-50 51-75 00-25 26-50 76-100 10.0.0.3 DC1: RF=3 51-75 26-50 00-25 Node Primary Replica Replica 10.0.0.1 00-25 76-100 51-75 10.0.0.2 26-50 00-25 76-100 10.0.0.3 51-75 26-50 00-25 10.0.0.4 76-100 51-75 26-50 25 

26 . Multi-datacenter AWS GCP Client 10.0.0.1 10.1.0.1 00-25 00-25 76-100 76-100 51-75 51-75 Write to partition 15 10.0.0.4 10.0.0.2 10.1.0.4 10.1.0.2 76-100 26-50 76-100 26-50 51-75 00-25 51-75 00-25 26-50 76-100 26-50 76-100 10.0.0.3 10.1.0.3 51-75 51-75 26-50 26-50 00-25 00-25 DC1: RF=3 DC2: RF=3 26 

27 . Multi-datacenter AWS GCP Client 10.0.0.1 10.1.0.1 00-25 00-25 76-100 76-100 51-75 51-75 Write to partition 15 10.0.0.4 10.0.0.2 10.1.0.4 10.1.0.2 76-100 26-50 76-100 26-50 51-75 00-25 51-75 00-25 26-50 76-100 26-50 76-100 10.0.0.3 10.1.0.3 51-75 51-75 26-50 26-50 00-25 00-25 DC1: RF=3 DC2: RF=3 27 

28 . Multi-datacenter AWS GCP Client 10.0.0.1 10.1.0.1 00-25 00-25 76-100 76-100 51-75 51-75 Write to partition 15 10.0.0.4 10.0.0.2 10.1.0.4 10.1.0.2 76-100 26-50 76-100 26-50 51-75 00-25 51-75 00-25 26-50 76-100 26-50 76-100 10.0.0.3 10.1.0.3 51-75 51-75 26-50 26-50 00-25 00-25 DC1: RF=3 DC2: RF=3 28 

29 . Data Modeling 29