What does these Cassandra warnings mean: Unable to lock JVM memory and MemoryMeter uninitialized

Question

I'm getting the following warnings on Cassandra - what does it mean? And is it an issue? And how can I solve this?

WARN 15:32:06,772 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.

WARN 15:33:20,860 MemoryMeter uninitialized (jamm not specified as java agent); assuming liveRatio of 10.0. Usually this means cassandra-env.sh disabled jamm because you are using a buggy JRE; upgrade to the Sun JRE instead

I'm using Cassandra 1.1.2.

Answer 1

ENOMEM is a Linux Error code for Out Of Memory. Cassandra has used all its virtual memory so the JVM can't lock additional memory resource from the virtual memory.

Jamm (Java Agent for Memory Management) provided MemoryMeter. What I see is that you don't have MemoryMeter installed and setup as an agent, so Cassandra disabled MemoryMeter. Also, MemoryMeter might only work for Sun Oracle JRE, and Cassandra prefers it if you want MemoryMeter to run successfully.

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To add Jamm to the Java Agent, add the following argument to the java process (example):

-javaagent:bin/../lib/jamm-0.2.5.jar 

(where the path is the path where the jar resides).