July 9th, 2013

 “Eventually consistent does not mean a day, minute or even second from now… in most cases, it is milliseconds!”


This session will address Cassandra’s tunable consistency model and cover how developers and companies should adopt a more Optimistic Software Design model.


Question Posed

“Can I trust that Cassandra will replicate my data when writing in CL1?”


A Netflix Experiment

• Created a multi-datacenter C* 1.1.7 Cluster of 48 nodes in each datacenter

• Put load in C* cluster 

        – 100k total operations per second (50k in each datacenter)

• Wrote 1,000,000 records at CL1 in one datacenter

• Read same 1,000,000 records at CL1 in other datacenter

• All records read successfully

• You can trust it!


Hurdles to Eventual Consistency

• In the engineering world: 1 + 1 = 2… not “eventually 2”

• Middle management is scared

        You’ve convinced them to use C*…

        – Now you need to convince them to accept low consistency?

• Engaging product teams to implement a contingency plan


Overcoming the Hurdles

• Prove it through a proof of concept

• Show them an improved user experience 

        – It’s all about the user!