Azul Zing gc collection

Question

We are investigating an application running of azul jvm (Zing release : 1.7.0-zing_15.05.3.0-b3-product-azlinuxM-X86_64).
Would appreciate with some pointers on making sense of the gc logs on Zing. JVM flags - `

-Xmx48g -XX:+ConcurrentDeflation -XX:+ScanSystemDictionaryBeforeUnload -XX:-ClassUnloading -XX:+KeepSafepointsInCountedLoops -XX:+UseOptimizedCollectionsIterator` 
-XX:StringTableSize=100019

We need to figure out if the JVM was struggling at any point with garbage - but do not know the exact keywords to fetch in the log.

Answer 1

Your JVM flags show you're not generating GC log information. To do this you will need to add the -xloggc:[filename] option. You could also specify -XX:+PrintGCDetails to generate the detailed logging output. You can find more details in the Zing documentation, http://docs.azul.com/zing/index.htm#ReferenceMaterials.htm. There are sections on command line options and GC log files.