nodetool flush 

Flushes one or more tables from the memtable.

Flushes one or more tables from the memtable.

Synopsis 

$ nodetool <options> flush -- <keyspace> ( <table> ... )
Options
Short Long Description
-h --host Hostname or IP address.
-p --port Port number.
-pwf --password-file Password file path.
-pw --password Password.
-u --username Remote JMX agent username.
keyspace Name of keyspace.
table One or more table names, separated by a space.
-- Separates an option from an argument that could be mistaken for a option.

Description 

You can specify a keyspace followed by one or more tables that you want to flush from the memtable to SSTables on disk.