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From Daniel Doubleday <daniel.double...@gmx.net>
Subject Re: Cassandra memory problem
Date Mon, 04 Jul 2011 15:01:57 GMT
Just to make sure: 
You were seeing that res mem was more than twice of max java heap and that did change after
you tweaked GC settings?

Note that I am not having a heap / gc problem. The VM itself thinks everything is golden.

On Jul 4, 2011, at 3:41 PM, Sebastien Coutu wrote:

> We had an issue like that a short while ago here. This was mainly happening under heavy
load and we managed to stabilize it by tweaking the Young/Old space ratio of the JVM and by
also tweaking the tenuring thresholds/survivor ratios. What kind of load to you have on your
systems? Mostly reads, writes?
> 
> SC
> 
> On Mon, Jul 4, 2011 at 6:52 AM, Daniel Doubleday <daniel.doubleday@gmx.net> wrote:
> Hi all,
> 
> we have a mem problem with cassandra. res goes up without bounds (well until the os kills
the process because we dont have swap)
> 
> I found a thread that's about the same problem but on OpenJDK: 
> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Very-high-memory-utilization-not-caused-by-mmap-on-sstables-td5840777.html
> 
> We are on Debian with Sun JDK.
> 
> Resident mem is 7.4G while heap is restricted to 3G.
> 
> Anyone else is seeing this with Sun JDK?
> 
> Cheers,
> Daniel
> 
> :/home/dd# java -version
> java version "1.6.0_24"
> Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
> Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02, mixed mode)
> 
> :/home/dd# ps aux |grep java
> cass     28201  9.5 46.8 372659544 7707172 ?   SLl  May24 5656:21 /usr/bin/java -ea -XX:+UseThreadPriorities
-XX:ThreadPriorityPolicy=42 -Xms3000M -Xmx3000M -Xmn400M ...
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                
                                                                                         
                                      
> 28201 cass      20   0  355g 7.4g 1.4g S    8 46.9   5656:25 java
> 
> 
> 
> 


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