Blog

Posted 2005/12/22

How low can you go?

While running the many mediator tests on Starbug I started to run out of memory so I have been trying to find how low I can set the Java heap.

With 1000 mediators on 8 nodes you have 125 Java JVMs sharing 2GB of RAM. I want to hold off swapping as long as possible (since performance will deteriorate then) so I started to reduce the heap size until I got out of memory. I am now rerunning the many mediator tests with java -Xms1m -Xmx3m this + the size of a JVM gives around 29-35MB of RAM total per mediator (which includes a full copy of HSQLDB and Jetty :).

Unfortunately even this hardcore heap size Starbug will probably run out of RAM by around 500 mediators. We shall see.