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From Martin Gainty <mgai...@hotmail.com>
Subject RE: heap memory issues
Date Mon, 18 Jun 2012 23:26:13 GMT

Chris Hansen sugire:

Thread maximum stack size 2m
Initial stack is 32m
Initial PermGen 32m
Max PermGen 200m
Max Heap at 367 M
Allow Concurrent Mark and Sweep
CMS ClassUnloading enabled
-Xss2m 
-Xms32m 
-XX:PermSize=32m 
-XX:MaxPermSize=200m 
-Xverify:none 
-Xmx367m 
-XX:+UseConcMarkSweepGC 
-XX:+CMSClassUnloadingEnabled 


http://my.opera.com/karmazilla/blog/2007/03/13/good-riddance-permgen-outofmemoryerror?cid=2666067#comment2666067
http://publib.boulder.ibm.com/infocenter/javasdk/v6r0/index.jsp?topic=%2Fcom.ibm.java.doc.diagnostics.60%2Fdiag%2Fappendixes%2Fcmdline%2Fcommands_jvm.html

Saludos Cordiales,
Martin 
______________________________________________ 
Porfavor..no altere esta communicacion..Gracias


> Date: Tue, 19 Jun 2012 00:34:46 +0200
> From: miguel_3_gonzalez@yahoo.es
> To: users@tomcat.apache.org
> Subject: Re: heap memory issues
> 
> On 18/06/2012 09:52, Konstantin Kolinko wrote:
> > 2012/6/16 Miguel González Castaños<miguel_3_gonzalez@yahoo.es>:
> >> Dear all,
> >>
> >>    We have a webapp under Tomcat 5.5 and jdk 1.5 32 bits under a virtual
> >> machine of 4 Gb and a 64 bits OS.
> > 4 Gb is memory size?
> Yes
> >
> >>    Some of you have helped me suggesting me to install Javamelody and sar to
> >> monitor the system. Setting up heap dumps I have managed to see what was
> >> going on with the eclipse memory analyzer.
> >>
> >>    The webapp sends emails that have been previously entered into the
> >> database. It loads the emails into memory, so if you are sending 10k emails,
> >> it loads 10k objects containing those emails. That makes the app to use
> >> around 200-300 mb of the heap memory.
> > Do you need to keep 10k of them in the memory at the same time?
> > Usually one would send mails one by one and release their memory
> > immediately.
> I don't. Fortunately the developer has corrected this, so probably other 
> issues will arise but not this one.
> >
> >
> >>   The settings we have now for the JDK are:
> >>
> >>   CATALINA_OPTS="$CATALINA_OPTS -XX:+HeapDumpOnOutOfMemoryError
> >> -XX:HeapDumpPath=/opt/tomcat5/logs/ -Xms128m -Xmx512m -verbose:gc
> >> -XX:+PrintGCTimeStamps -XX:+PrintGCDetails"
> >>
> >>   Facts that I have witnessed:
> >>
> >>   If I try to increase the Xmx to 740m or 1024m the GC starts working very
> >> much and Tomcat shuts down.
> > GC? Or OS memory swapping?
> GC, no swapping reported by sar.
> >
> >>   I have also tried downloading a 64 bits 1.7 jdk but I get the typical:
> >>
> >>   Java HotSpot(TM) 64-Bit Server VM warning: Exception
> >> java.lang.OutOfMemoryError occurred dispatching signal SIGTERM to handler-
> >> the VM may need to be forcibly terminated
> > 64-bit JVM usually needs more memory than 32-bit one,  because memory
> > address range is wider and pointers need more memory.
> I know, but how do I know how much ram to assign in a 64 bits jdk? We 
> are planning to move to a bigger server (hopefully 16 or 32 gb).
> 
> Miguel
> 
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