Cassandra Insufficient user resource limits errors

Insufficient resource limits may result in a number of errors in Cassandra and OpsCenter.

Cassandra errors 

Insufficient as (address space) or memlock setting 

ERROR [SSTableBatchOpen:1 ] 2012-07-25 15:46:02,913 AbstractCassandraDaemon.java  (line 139)
Fatal exception in thread Thread [SSTableBatchOpen:1,5,main ]
java.io.IOError: java.io.IOException: Map failed  at ...

Insufficient memlock settings

WARN [main ] 2011-06-15 09:58:56,861 CLibrary.java  (line 118) Unable to lock JVM memory  (ENOMEM).
This can result in part of the JVM being swapped out, especially with mmapped I/O enabled.
Increase RLIMIT_MEMLOCK or run Cassandra as root.

Insufficient nofiles setting

WARN 05:13:43,644 Transport error occurred during acceptance of message.
org.apache.thrift.transport.TTransportException: java.net.SocketException:
Too many open files ...

Insufficient nofiles setting

ERROR [MutationStage:11 ] 2012-04-30 09:46:08,102 AbstractCassandraDaemon.java  (line 139)
Fatal exception in thread Thread [MutationStage:11,5,main ]
java.lang.OutOfMemoryError: unable to create new native thread

Recommended settings  

You can view the current limits using the ulimit -a command. Although limits can also be temporarily set using this command, DataStax recommends making the changes permanent:  

Packaged installs: Ensure that the following settings are included in the /etc/security/limits.d/cassandra.conf file:

cassandra - memlock unlimited
cassandra - nofile 100000
cassandra - nproc 32768
cassandra - as unlimited

Tarball installs: Ensure that the following settings are included in the /etc/security/limits.conf file:

* - memlock unlimited
* - nofile 100000
* - nproc 32768
* - as unlimited

If you run Cassandra as root, some Linux distributions such as Ubuntu, require setting the limits for root explicitly instead of using *:

root - memlock unlimited
root - nofile 100000
root - nproc 32768
root - as unlimited

For CentOS, RHEL, OEL systems, also set the nproc limits in /etc/security/limits.d/90-nproc.conf :

* - nproc 32768

For all installations, add the following line to /etc/sysctl.conf :

vm.max_map_count = 131072

To make the changes take effect, reboot the server or run the following command:

$ sudo sysctl -p

To confirm the limits are applied to the Cassandra process, run the following command where pid is the process ID of the currently running Cassandra process:

$ cat /proc/<pid>/limits

Reference : http://docs.datastax.com/en/cassandra/2.0/cassandra/troubleshooting/trblshootInsufficientResources_r.html