Peter's option is a valid one. I use this approach myself to limit the size of PermGen. Of course, I may have more control over the apps than you do. If you do need to load different version, you should be able to put the alternate version in the apps WEB-INF/lib directory and the app's loader will prefer it. (at least at 5.5). One thing to watch out for. Some libraries do not "play nice". For instance, log4j gets instantiated once for the jvm. If you share the lg4j library but each app has its own log file definition, they will end up meshing into one log (I think the last one instantiated).
Jeff -----Original Message----- From: Peter Crowther [mailto:peter.crowt...@melandra.com] Sent: Thursday, May 28, 2009 4:03 AM To: 'Tomcat Users List' Subject: RE: MaxPermSize, Tomcat startup trouble By the way, there's one other thing you *could* try if you had to reduce memory usage. I don't like it, because it makes versioning the webapps a nightmare; but it might save you quite a lot of RAM and allow you to go live on the current hardware. The choice is yours! If many of your webapps use the same versions of the same jars, you *could* share them between webapps. The classes will then be loaded once, rather than once per webapp, reducing the amount of PermGen required. The problem, of course, is that your webapps are then locked to the same library versions - updating one webapp with a new library is a problem. If you want to look at this approach, check the Tomcat 6 classloader how-to on the web site. But if you do this, I would suggest you regard it as an emergency hack and look urgently at ways to remove it. - Peter ******************************* NOTICE ********************************* This message is intended for the use of the individual or entity to which it is addressed and 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 or the employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by reply or by telephone (call us collect at 512-343-9100) and immediately delete this message and all its attachments. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
