Blindly following http://wiki.apache.org/cassandra/CassandraCli, and can someone please explain this?
aaron-mac:apache-cassandra-1.0.0 aaron$ bin/cassandra-cli
That's for an older version of Cassandra. Keys are now treated as hex bytes by default, so you need:
set User[utf8('jsmith')]['first'] = 'John';
or do:
assume User keys as utf8;
set User['jsmith']['first'] = 'John';
Or, as the note in the doc says:
Note: As of Cassandra 0.8, we need to declare a key_validation_class for the column family:
update column family User with key_validation_class=UTF8Type;