A transaction cannot leave the database in an inconsistent state. Cassandra offers different types of consistency.
- Tunable consistency
Availability and consistency can be tuned, and can be strong in the CAP sense--data is made consistent across all the nodes in a distributed database cluster.
- Linearizable consistency
In ACID terms, linearizable consistency is a serial (immediate) isolation level for lightweight transactions.
For in-depth information about this new consistency level, see the article, Lightweight transactions in Cassandra.