So are you saying that I shouldn't use the shared lib at all?...or just sparingly?
On Fri, Oct 9, 2009 at 12:36 PM, Caldarale, Charles R <chuck.caldar...@unisys.com> wrote: >> From: Curtis Garman [mailto:curt.gar...@gmail.com] >> Subject: tomcat 5.5.25 shared lib and sharing webapp jars >> >> I've got a question about the tomcat 5.5.25 shared lib...is there any >> danger of using this almost exclusively if you have a lot of jars that >> are shared among apps. > > The danger is that you have essentially glued all your webapps together, and > you may not be able to manipulate (stop/redeploy/start) them individually > without serious impacts to the heap, especially PermGen. > >> I know you can but I also saw something somewhere and now again >> (http://www.digitalsanctum.com/2007/08/18/20-tips-for-using-tomcat-in- >> production/ >> - number 6) about garbage collection only operating on memory that was >> inside the scope of a specific app and because the shared lib stuff >> doesn't belong to specific app it wouldn't get cleaned up. > > That's not really what it says. GC knows nothing about the individual > webapps; it operates on the Java heap as a whole. The problem with sharing > libraries is that they can very easily retain references to caller's objects > and thereby prevent the calling classes from ever being unloaded when a > webapp is redeployed. > >> I've got a jvm in development that has about 20 apps in it...to reduce >> the heap size, I moved as many jars as I could to the shared lib >> folder... > > Probably a bad idea. Given the extremely low cost of RAM and the widespread > availability of 64-bit operating environments, you are likely practicing > false economy. > > - 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 > > -- Curtis Garman Web Programmer Heartland Community College --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
