Showing posts from November 11, 2010

Cassandra: What is HintedHandoff ?

Nate has a very good post about how Cassandra is different from a lot of other distributed data-stores. In particular he explains that every node in a Cassandra cluster are identical to every other node . After using cassandra and a few months I can tell you for a fact that its true. It does come at a price though. Because its so decentralized, if you want to make a schema change, for example, configuration files of all of the nodes in the cluster need to be updated all at the same time. Some of these problems will go away when 0.70 finally comes out . While is true that Cassandra doesn’t have a concept of single “master” server, each node participating in the cluster do actually act as masters and slaves of parts of the entire key range. The actual % size of the key range owned by an individual node depends on the replication factor, on how one picks the keys and what partitioner algorithm was selected. The fun starts when a node, which could be the master for a range of ke