On Wed, Dec 18, 2013 at 6:11 PM, Christopher Schultz < ch...@christopherschultz.net> wrote:
> 1. What JVM are you using? > > > Answer: [X] Sun/Oracle/OpenJDK Java 1.7 > > > 2. What kind of web application are you running? > > > Answer: [X] A moderately busy web site (<1M requests/mo/server) > 3. What is your total heap size? > -Xms4096m -Xmx4096m -XX:MaxPermSize=384m (will share this as well, just because) but I think I can change to -Xms/-Xmx1250m, because heap used seem to max out at (+/-)1024m. > > 4. Are you explicitly specifying a Garbage Collector? If not, just say > so and skip the rest of the questions. > -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled > > 5. What led you to use [GC X] instead of the JVM's default collector? > I've seen CMS recommended almost any/everywhere. > > 6. Did you do any actual performance testing to see if the switch from > the default to [GC X] made any difference? > No. > > 6. Have you spent a lot of time tuning [GC X]? > A little...over time. I primarily adjusted -Xms/-Xmx a few times. > > 7. Did your tuning exercise yield any useful results? > Yes. I don't experience OutOfMemory exceptions, and app runs just fine. > > 8. Did your users notice any difference after you implemented [GC X], > or just your own load-testing team? > No. My app has been configured to use CMS ever since the beginning of time/production. > > If you think there's anything else I should know about your experience > with [GC X], please let me know. > To answer #4, I searched google, and found this[1], and that helped me answer your question. :) I am sure that I can lower my -Xms/-Xmx4096m heap size, but with 32GB of RAM on the server, i'm not really pressed to do so. The server is used just for the app. [1] http://www.cubrid.org/blog/textyle/428187
