Tomcat Memory Usage (PermGen)

Question

I use Tomcat to deploy a web application with PermGen settings:

JAVA_OPTS="-Djava.awt.headless=true -Dfile.encoding=UTF-8 
-server -Xms1536m -Xmx1536m
-XX:NewSize=256m -XX:MaxNewSize=256m -XX:PermSize=256m 
-XX:MaxPermSize=256m -XX:+DisableExplicitGC"

Please, I want to know the following:

• Should all of the memory used by Tomcat be 256 MB, or does Tomcat consume other memory for other reasons?
• How can I control the memory used by Tomcat to avoid the maximum size of PemGen?

Also note that I have 3 Tomcats with the same previous PermGen configurations that run on the same physical server with 8 GB of RAM, which makes me afraid to increase the maximum PermGen size to 512 MB so as not to affect the physical memory of the server.

Answer 1

OOME Tomcat, , :

• .

• , .

, :

• . .

• , .

, , , OOME. ( / Tomcat .)

---

:

1). , Tomcat, 256 , Tomcat ?

. . Tomcat, Tomcat . (-, Hibernate ... , .)

2) , Tomcat, PemGen?

; . . IMO, (), .

Answer 2

Tomcat permgen , , webapps, (permgen ). jconsole , , → → Gen. Tomcat 7, -, 65M max 6M.