Introduction

Data stores, even when very different in purpose, often follow very similar approaches to clustering, high availability, failover, and more.

The aim of this specification is to define a model that details the attributes, behaviours, and expectations needed of data stores.

While the focus is describing data stores, the specification does so with support of agents. Agents are processes on top of a data store nodes to provide additional management functions that are not part of data store duties as well as an interface abstraction point.

What is a data store?

A data store is any software that stores state. State is some information that, if lost, can’t easily be regenerated.

For example:

• A list of users is state: if lost, users would have to re-register.
• A cached web page is NOT state: if lost, the page can be fetched from the origin.

This, combined with the fact that individual data store nodes can store up to several terabytes of data, means that simple operations may become slow, expensive and/or risky.

In this specification

• Attributes and Behaviours details what we can know of data stores and data store nodes and what they can do.
• The API Reference is available for both agent developers and clients.
• Examples are then provided of how some data store software map to this specification.
• The CHANGELOG page details the evolution of this specification.