Cassandra Clients approach any of the nodes for their read-write operations. Cassandra Provides below Operations That node (coordinator) plays a proxy between the client and the nodes holding the data.
1) Read Operations
During read operations, Cassandra gets values from the mem-table and checks the bloom filter to find the appropriate SSTable that holds the required data. Cassandrra Promotes Read Before Wite Operations.
2) Write Operations
Every write activity of nodes is captured by the commit logs written in the nodes. Later the data will be captured and stored in the mem-table. Whenever the mem-table is full, data will be written into the SStable data file. All writes are automatically partitioned and replicated throughout the cluster. Cassandra periodically consolidates the SSTables, discarding unnecessary data.