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From Russ Bradberry <rbradbe...@gmail.com>
Subject Re:
Date Wed, 12 Mar 2014 23:28:47 GMT
I wouldn't go above 8G unless you have a very powerful machine that can keep the GC pauses
low.

Sent from my iPhone

> On Mar 12, 2014, at 7:11 PM, Edward Capriolo <edlinuxguru@gmail.com> wrote:
> 
> That is too much ram for cassandra make that 6g to 10g. 
> 
> The uneven perf could be because your requests do not shard evenly.
> 
> On Wednesday, March 12, 2014, Batranut Bogdan <batranub@yahoo.com> wrote:
> > 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
> > Gigabit.
> >
> > 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
> > timeout. 
> >
> > 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.
> 
> -- 
> Sorry this was sent from mobile. Will do less grammar and spell check than usual.

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