On Thu, Apr 11, 2013 at 10:41 AM, Mark H. Wood <mw...@iupui.edu> wrote:
> Really, no one else can tell you what settings to use. The best we > can hope for is some accepted rules of thumb *as starting points* for > further tuning. > > +1 to Dan, Neven, and Mark's responses. Please consider-or-do 'everything' that they mentioned/recommended. I did want to share my java settings for my currently-considered-a-low-scale JSF web app running on Windows Server 2008 R2 64bit server with 32GB RAM. -XX:HeapDumpPath=D:\apache-tomee-plus-1.6.0-SNAPSHOT\temp -XX:+HeapDumpOnOutOfMemoryError -Djava.awt.headless=true -Dcom.sun.management.jmxremote.port=422 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Xms1024m -Xmx1024m -XX:MaxPermSize=384m -XX:+UseTLAB -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled I am very pleased with the GC performance of my app, and I do like to monitor the performance of the app via JMX remote connection via Java Visual VM. My app runs between 200m to 500m, but I am keeping Xms/Xmx=1024m just to see if I ever get an OOME; so far, so good (never experienced an OOME), but recently, I did experience some unexpected/unwanted behavior with one of my @Schedule processes which was attempting to sync some data from database to/with Google Calendar, and google Calendar service returned google calendar error 503, and I recognized that the memory got up to 500m, and the google calendar error 503 did not resolve itself over an hour (@Schedule executes every 2 to 4 minutes, if error occurs, then data is appended to the queue for later retry attempt). I never seen that behavior and I don't know if I will see it again; i wish I would have done a 'heap dump' instead of a 'stop' tomee/tomcat. Everyday, I listen and read these questions/responses on tomcat list, and I can't believe that I forgot to do a 'heap dump'. :( Also, please note that I occasionally stop-deploy-and-start tomee/tomcat almost-on-a-daily-basis to deploy new app-or-configuration-or-library updates; also, the app or tomee (or tomcat) seem to accumlate threadlocals over time, and if uptime is > 1 day, then I 'think' I see that memory is not released, and I think eventually as uptime increases, then the app/tomee/tomcat will result in OOME. :) At any rate, hope this helps. Howard
