It supports two consistencies :
* Eventual Consistency
* Strong Consistency.
* The eventual consistency is used when no new updates are made on a given data item, all accesses return the last updated value eventually. Systems with eventual consistency are known to have achieved replica convergence.
* Cassandra supports the following conditions for strong consistency:
R + W > N
Here
N: Number of replicas
W: Number of nodes that need to agree for a successful write
R: Number of nodes that need to agree for a successful read
