This was presented for an O'Reilly Media webcast. http://www.oreilly.com/pub/e/3152?cmp=tw-na-webcast-product-webcast_an_introduction_to_apache_accumulo
This webcast will cover the basics of Apache Accumulo architecture and how it works, along with examples of how it is used. We'll also talk about some interesting use cases, such as text indexing, fine-grained multi-level access controls, and storing large-scale graphs. We'll also briefly touch on what sets Accumulo apart from other similar and not-so similar systems and where we think the Accumulo project is headed in a technical direction.
A description of Accumulo from the Apache Accumulo website:
The Apache Accumulo sorted, distributed key/value store is a robust, scalable, high performance data storage and retrieval system. Apache Accumulo is based on Google's BigTable design and is built on top of Apache Hadoop, Zookeeper, and Thrift. Apache Accumulo features a few novel improvements on the BigTable design in the form of cell-based access control and a server-side programming mechanism that can modify key/value pairs at various points in the data management process. Other notable improvements and feature are outlined here. Google published the design of BigTable in 2006. Several other open source projects have implemented aspects of this design including HBase, Hypertable, and Cassandra. Accumulo began its development in 2008 and joined the Apache community in 2011.