> From: Robinson, Eric [mailto:eric.robin...@psmnv.com] > Subject: Understanding Tomcat Memory Utilization > > Can someone help me understand why tomcat is configured to > use 64MB, but claims to peak at 48MB
Because that's all it needs to initialize. Unless you set -Xms == -Xmx, the JVM starts out with a smaller heap than the max, and even after the max has been reached, it may shrink the heap size back down if it can. > but has resident size of 147MB, and a virtual size of 256MB, > while other instances of tomcat have java processes with a > resident size of 32MB? Welcome to paging. The Linux memory subsystem will swap out least recently used pages when needed to make room for others. I suspect the ones with the smaller resident sizes initialized first, went idle, and some of their memory was swapped out to make room for the later ones. If you're not seeing paging activity during heavy loads, you're fine. If you are, you'll need to increase the amount of RAM on the system, since you're not going to be able to decrease the JVM heap sizes to any significant degree (64 MB is pretty small these days). - 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
