Reading for ParNew (promotion failed) and (concurrent mode failure)

http://java-monitor.com/forum/showthread.php?t=645 Dear All, If you are struggling to understand the messages ParNew (promotion failed) and (concurrent mode failure), you might want to bone up on memory management and garbage collector internals. ParNew (promotion failed): This means that your old generation has become fragmented and the data from Eden might not fit into a large enough contiguous chunk in old. https://java.sun.com/j2se/reference/...whitepaper.pdf http://blogs.sun.com/jonthecollector...the_sum_of_the (concurrent mode failure): The GC predicts that the CMS collection will not complete in time before the Old generation becomes full. It aborts the run and does a stop-the-world instead. http://blogs.sun.com/jonthecollector...t_the_heck_s_a Kees Jan Dear All, Oh, and how to resolve these? Well, you have to experiment. Each option has downsides and may or may not make them unusable for your situation. Sorry, but there is no clear-cut answer. ParNew (promotion failed): reduce Eden size, increase heap size. (concurrent mode failure): make the GC kick in sooner with -XX:+CMSIncrementalMode and/or setting -XX:CMSInitiatingOccupancyFraction to lower than the default value. Here is documentation on the JVM switches: http://blogs.sun.com/watt/resource/j...ions-list.html Kees Jan