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From Daniel Doubleday <daniel.double...@gmx.net>
Subject Re: JNA to avoid swap but physical memory increase
Date Fri, 15 Jul 2011 11:24:40 GMT
When using jna the mlockall call will result in all pages locked in rss and thus reported there
so you have either configured -Xms650M or you are running on a small box and the start script
calculated it for you.

Also our experience shows that the jna call does not prevent swapping so the general advice
is disable swap.

If you had data in you server and did read requests some (partially) loaded sstables would
show up in rss too.

Also there is https://issues.apache.org/jira/browse/CASSANDRA-2868


On Jul 15, 2011, at 10:46 AM, Donna Li wrote:

> All:
> I download JNA jar and put it to cassandra lib directory. When restart cassandra server,
I found the physical memory highly increase. There is no data saved in cassandra, why so much
memory used by cassandra? How can I decrease the memory usage by cassandra? My version is
0.7.6-2.
>  
>  
> Before
> PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND 
> 11381 root      25   0  653m  57m 6272 S    0  5.7   0:02.33 java    
>  
> After
> PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND 
> 11130 root      25   0  653m 647m 9.9m S    0 64.2   0:03.57 java      
>  
>  
> Best Regards
> Donna li


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