> -----Original Message----- > From: Caldarale, Charles R [mailto:chuck.caldar...@unisys.com] > Sent: Wednesday, September 29, 2010 9:12 AM > To: Tomcat Users List > Subject: RE: apache-tomcat-6.0.29 will not start with more then 1024mb > memory assigned - windows > > > From: Hans Magne Helland [mailto:hansma...@gmail.com] > > Subject: Re: apache-tomcat-6.0.29 will not start with more then > 1024mb memory assigned - windows > > > This tomcat server is running an ARS Remedy Mid-Tier application > > (version 7.5), the requirements from BMC on this version is that it > > must be a 32bit tomcat install using a 32bit java. > > Since I'm not familiar with BMC's products, that didn't really answer > the question: does the webapp include native code? If not, then the > webapp won't be able to tell the difference between 32- and 64-bit > JVMs. Have you tried running it on a 64-bit JVM? > > > > So 1024mb looks to be the limit on a 32bit java/tomcat install? > > The exact limit varies depending on the details of the process. Native > code inside the JVM process may well limit the amount of contiguous > virtual space remaining that the heap has to fit into. There are > configuration options for 32-bit Windows to allow a 3 GB process space > instead of the normal 2 GB, but that puts other constraints on the OS. > Not sure what can be done on a 64-bit Windows, since the expectation is > that serious apps will be using 64-bit processes. > > - Chuck >
Chuck is right on the limits above. I've managed to eek out 1536Mb on most of my 32-bit installs using Java 5/6 and Tomcat 5.5 (we've not moved to TC6 yet - next project). Even with the 3Gb option set on the 32-bit Windows, I couldn't get much higher (search archives for exact number). I haven't found any way comparable option for the 32-bit environment on the 64-bit O/S versions, but then again, I haven't looked. If I have 64-bit O/S, I use 64-bit Java. One thing to note that Chuck mentioned, is there are other factors involved in all that memory management. Beyond any native code requirements, there are other things like PermGen size settings that might affect the max memory size. I recently had a baffling problem when trying to increase my PermGen space. On one system, I had increased the MaxPermGen setting to 256Mb and everything was fine. When I went to an identically configured machine, Tomcat would not start with that large a setting. I could get 160Mb to startup. I didn't try any higher values to see what the max was, I could just tell that I was hitting some limit. Then I noticed that there was a slight variance in the Tomcat configs. The second machine had a higher Max Memory Pool (Heap) than the first by about 512Mb. So there is some tradeoff between PermGen space and Heap. Check all the other settings that BMC said you needed to set, and see if there is something there stealing the available space. Currently, I monitoring the two systems to see if there is an optimal PermGen vs. Heap setting for their specific loads (which are different). __________________________________________________________________________ Confidentiality Notice: This Transmission (including any attachments) may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this transmission in error, please immediately reply to the sender or telephone (512) 343-9100 and delete this transmission from your system. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
