Perfect :) I test it.
I didn't open this file before. I did think the configuration only was in
the foloder conf.
I am not a specialist java. I will search about the meaning of JVM
parameters.

  For now, I read this page for undertand the others options of JVM :
http://java.sun.com/performance/reference/whitepapers/tuning.html

Thanks Oleg.



2010/6/1 Oleg Anastasjev <oleganas@gmail.com>

> xavier manach <xav <at> tekio.org> writes:
>
> >
> > Hi.  I search informations for basic tunning of memory in Cassandra.My
> situation :  I started to test larges imports of data in Cassandra 6.1.Myfirst
> import worked fine : 100 Millions row in 2 hours ~ around 10000 insert row
> by
> seconds
> > My second is slower with the same script in another column family :  ~
> around
> 500 insert row by seconds...I didn't understand why I have a lot of GC for
> ConcurrentMarkSweep.[ GC for ConcurrentMarkSweep: 3437 ms, 104971488
> reclaimed
> leaving 986519328 used; max is 1211170816. ]
> > ( The max did'n't move, what is this value 1211170816 ? ) I think the GC
> process appear when the insert is slow. The inserts didn't work when the GC
> works ?My machine has 66M of RAM, and the processor java only use around
> 1.8 %
> > How Can I optimise the use of memory ?There is a the guideline for best
> performances ?Thanks.
>
>
> You may run out of memory. Cassandra stores some information about those
> 100M
> rows you just inserted in RAM. By default cassandra is configured to take
> up to
> 1Gb of RAM. You can configure more memory for cassandra by editing
> bin/cassandra.in.sh. Look there for -Xmx1G and change it to your taste.
>
>
>