Do a simple math. If you give each VM up to 384M heap and if you add some 100 MB for permspace and overhead, you have a consumption of 500MB per VM. Take 1GB for OS needs, you have 15, and 15.000/500 makes it save to run 30 tomcat instances max. Since you experience the problems after some running time, I would assume that you VMs are starting with 128 but slowly take up all the space, and the later VMs just have nothing to get. Advice: Calculate your needs exactly by playing with settings (remember always set Ms=Mx) and watching gc logs. You will probably need to reduce the number of instances or buy another machine (or put more memory into this one). Also, do you really need a separate instance for each webapp? You have 60x catalina code in the heap and everything, which probably takes half of your memory. regards Leon
On Mon, Dec 19, 2011 at 8:24 PM, Caldarale, Charles R <chuck.caldar...@unisys.com> wrote: >> From: Robinson, Eric [mailto:eric.robin...@psmnv.com] >> Subject: Do I Have Java Memory Fragmentation? > >> All of this makes me think we have a problem with Java memory >> fragmentation because of having so many instances of Java > > Fragmentation doesn't really exist anymore, thanks to paging and garbage > collection. (Except in very unusual circumstances involving badly coded JNI > methods that pin objects unnecessarily; are you doing that?) > >> Can someone recommend a way to diagnose and/or fix this problem? > > Look in the Windows logs (event viewer), not the Tomcat ones. Windows may > think you're running out of memory + swap space. Raising the -Xmx value for > each Tomcat instance will only make it worse, not better. > > - Chuck > > > THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY > MATERIAL and is thus for use only by the intended recipient. If you received > this in error, please contact the sender and delete the e-mail and its > attachments from all computers. > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
