Product

Product: Project Voldemort - A Distributed Database

Todd Hoff

Jul 1, 2009 — 1 min read

Update: Presentation from the NoSQL conference: slides, video 1, video 2.

Project Voldemort is an open source implementation of the basic parts of Dynamo (Amazon’s Highly Available Key-value Store) distributed key-value storage system. LinkedIn is using it in their production environment for "certain high-scalability storage problems where simple functional partitioning is not sufficient."

From their website:

Data is automatically replicated over multiple servers.

Data is automatically partitioned so each server contains only a subset of the total data

Server failure is handled transparently

Pluggable serialization is supported to allow rich keys and values including lists and tuples with named fields, as well as to integrate with common serialization frameworks like Protocol Buffers, Thrift, and Java Serialization

Data items are versioned to maximize data integrity in failure scenarios without compromising availability of the system

Each node is independent of other nodes with no central point of failure or coordination

Good single node performance: you can expect 10-20k operations per second depending on the machines, the network, and the replication factor

Support for pluggable data placement strategies to support things like distribution across data centers that are geographical far apart.

They also have a nice design page going over some of their architectural choices: key-value store only, no complex queries or joins; consistent hashing is used to assign data to nodes; JSON is used for schema definition; versioning and read-repair for distributed consistency; a strict layered architecture with put, get, and delete as the interface between layers.

Just a hint when naming a project: don't name it after one of the most popular key words in muggledom. The only way someone will find your genius via search is with a dark spell. As I am a Good Witch I couldn't find much on Voldemort in the real world. But the idea is great and is very much in line with current thinking on scalable database design. Worth a look.

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