Overview of virtual nodes (vnodes).
Vnodes simplify many tasks in Cassandra:
- You no longer have to calculate and assign tokens to each node.
- Rebalancing a cluster is no longer necessary when adding or removing nodes. When a node joins the cluster, it assumes responsibility for an even portion of data from the other nodes in the cluster. If a node fails, the load is spread evenly across other nodes in the cluster.
- Rebuilding a dead node is faster because it involves every other node in the cluster.
- Improves the use of heterogeneous machines in a cluster. You can assign a proportional number of vnodes to smaller and larger machines.
For more information, see the article Virtual nodes in Cassandra 1.2 and Enabling virtual nodes on an existing production cluster.