2011/2/8 Robinson, Eric <eric.robin...@psmnv.com> > > Obviously I need to understand this better. If all instances are set to > -Xmx512M and then one instance peaks to 512M and even tries to go above > that (and therefore generates an OOME) how does that impact the other > instances? Does an OOME mean there is no more memory available from the > OS? I thought it just meant it had used the max memory allowed by the > -Xmx setting. That should not cause a problem for other instances should > it? > > --Eric
Eric, what Chris is trying to explain is that a single instance using 512M may not right then have adverse effects on others as long as the real memory available is not exhausted and paging has started at the OS level. However, increasing this limit for all instances may lead to a situation where enough instances are claiming more memory at the same time and beyond the physical memory available. At that point, the system (OS) will start paging, provided you have paging space. It may be still runnable and usable at this point until too many memory is claimed and consume at the same time the OS enter the thrashing state. Paging is not necessarily bad, thrashing is the point where paging activity is so high no useful work but paging take place. The system is no longer usable at this point. Hope I was able to clarify Chris' point a little bit. Regards, -- ----------------- Daniel Savard CiDS Inc. Montreal, QC Canada --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
