Where you store your data. It is the basic infrastructure component of Cassandra.

A collection of related nodes. A datacenter can be a physical datacenter or virtual datacenter. Different workloads should use separate datacenters, either physical or virtual. Replication is set by datacenter. Using separate datacenters prevents Cassandra transactions from being impacted by other workloads and keeps requests close to each other for lower latency. Depending on the replication factor, data can be written to multiple datacenters. datacenters must never span physical locations.

A cluster contains one or more datacenters. It can span physical locations.

All data is written first to the commit log for durability. After all its data has been flushed to SSTables, it can be archived, deleted, or recycled.

A sorted string table (SSTable) is an immutable data file to which Cassandra writes memtables periodically. SSTables are append only and stored on disk sequentially and maintained for each Cassandra table.

A collection of ordered columns fetched by table row. A table consists of columns and has a primary key.