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From Rob Coli <>
Subject Re: cassandra 1.0.8 memory usage
Date Fri, 12 Oct 2012 21:59:30 GMT
On Fri, Oct 12, 2012 at 1:26 AM, Daniel Woo <> wrote:
>>>What version of Cassandra? What JVM? Are JNA and Jamm working?
> cassandra 1.0.8. Sun JDK 1.7.0_05-b06, JNA memlock enabled, jamm works.

The unusual aspect here is Sun JDK 1.7. Can you use 1.6 on an affected
node and see if the problem disappears?

Exists in 1.1.x (not your case) and is for leaking descriptors and not
memory, but affects both 1.6 and 1.7.

> JMAP shows that the per gen is only 40% used.

What is the usage of the other gens?

> I have very few column families, maybe 30-50. The nodetool shows each node
> has 5 GB load.

Most of your heap being consumed by 30-50 columnfamilies MBeans seems excessive.

>>> Disable swap for cassandra node
> I am gonna change swappiness to 20%

Even setting swappiness to 0% does not prevent the kernel from
swapping if swap is defined/enabled. I re-iterate my suggestion that
you de-define/disable swap on any node running Cassandra. :)


=Robert Coli
YAHOO - rcoli.palominob
SKYPE - rcoli_palominodb

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