Big movies, big data: Netflix embraces NoSQL in the cloud

With billions of reads and writes daily, Netflix relies on NoSQL database Cassandra to replace a legacy Oracle deployment

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The company chose Cassandra from DataStax for its flexibility to create and manage data clusters quickly, particularly in the cloud. Christos Kalantzis, Netflix's manager of cloud and platform engineering, explains that "solutions like Oracle don't run very well on virtualized hardware ... the architecture of Cassandra and the availability and consistency tuning and scalability made it a clear choice." To address these problems, Netflix initially migrated data from Oracle to Amazon's SimpleDB distributed database -- and eventually moved that data to Cassandra.

"With Cassandra, we get better business agility," Cockcroft says. "We don't have to plan capacity in advance, we don't need to ask permission of other people to build things for us, and we don't worry about running out of space or power. I can create a Cassandra cluster in any region of the world in 10 minutes," says Cockcroft. "When the marketing guys decide we want to move into a certain part of the world, we're ready."

In addition, downtime due to schema changes is no longer required. "There are no schemas to change in Cassandra -- therefore, there's no downtime," Cockcroft says.

Of course, with multiple Cassandra instances, there are more systems to manage than with the monolithic Oracle database. But Cockcroft points out, "They tend to break at different times, so you're losing small pieces of the system, rather than the whole system at once. Also, each store is simpler to administer."

Today, Cassandra is the preferred database for almost all database needs at Netflix. The company stores 95 percent of all its data in Cassandra, including customer account information, movie ratings, movie metadata, movie bookmarks, and logs.

Netflix operates more than 50 Cassandra clusters with over 750 nodes. At peak they process more than 50,000 reads per second and 100,000 writes per second across all their clusters. On average they process more than 2.1 billion reads in one day and more than 4.3 billion writes in one day.

Cassandra is has provided a new, more solid foundation for Netflix. As Cockcroft says, "It makes it possible for us to deliver the service our members rely on."

This article, "Big movies, big data: Netflix embraces NoSQL in the cloud," was originally published at Read more of Andrew Lampitt's Think Big Data blog, and keep up on the latest developments in big data at For the latest business technology news, follow on Twitter.

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