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From Batranut Bogdan <>
Subject [No Subject]
Date Wed, 12 Mar 2014 20:26:55 GMT
Hello all,

The environment:

I have a 6 node Cassandra cluster. On each node I have:
- 32 G RAM
- 24 G RAM for cassa
- ~150 - 200 MB/s disk speed
- tomcat 6 with axis2 webservice that uses the datastax java driver to make
asynch reads / writes 
- replication factor for the keyspace is 3

All nodes in the same data center 
The clients that read / write are in the same datacenter so network is

Writes are performed via exposed methods from Axis2 WS . The Cassandra Java
driver uses the round robin load balancing policy so all the nodes in the
cluster should be hit with write requests under heavy write or read load
from multiple clients.

I am monitoring all nodes with JConsole from another box.

The problem:

When wrinting to a particular column family, only 3 nodes have high CPU load
~ 80 - 99 %. The remaining 3 are at ~2 - 10 % CPU. During writes, reads

I need more speed for both writes of reads. Due to the fact that 3 nodes
barely have CPU activity leads me to think that the whole potential for C*
is not touched.

I am running out of ideas...

If further details about the environment I can provide them.

Thank you very much.
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