[kubuntu] Cassandra Database Error

Hi am starting cassandra Multinode Cluster from my environment am not good at cassandra its throwing one error message on my console Like

/lib/jamm-0.2.5.jar
INFO 10:48:59,526 JNA not found. Native methods will be disabled.
INFO 10:48:59,689 Loading settings from file:/cassendra/apache-cassandra-1.2.2/conf/cassandra.yaml
INFO 10:49:01,663 32bit JVM detected. It is recommended to run Cassandra on a 64bit JVM for better performance.
ERROR 10:49:01,698 Fatal configuration error
org.apache.cassandra.exceptions.ConfigurationExcep tion: Missing required directive CommitLogSync
at org.apache.cassandra.config.DatabaseDescriptor.loa dYaml(DatabaseDescriptor.java:154)
at org.apache.cassandra.config.DatabaseDescriptor.<cl init>(DatabaseDescriptor.java:122)
at org.apache.cassandra.service.CassandraDaemon.setup (CassandraDaemon.java:150)
at org.apache.cassandra.service.CassandraDaemon.activ ate(CassandraDaemon.java:366)
at org.apache.cassandra.service.CassandraDaemon.main( CassandraDaemon.java:409)
Missing required directive CommitLogSync
Fatal configuration error; unable to start server. See log for stacktrace.






if any one have any idea about this please let me know
Thanks