Re: [thredds] TDS4 Memory settings: PermGen?

We (they) were playing with this in the THREDDS class, and if I was keeping up correctly, increasing the size of the MaxPermSize had some delaying effect in some cases. The delaying effect didn't seem that significant to me, and wasn't all that predictable from what I saw.

Yeah, the message was restart Tomcat relatively often compared to the number of reloads, especially if you're on a production server.

John



On Aug 26, 2009, at 8:50 AM, Rich Signell wrote:

THREDDS Folk

To my chagrin, I just noticed that I asked a PermGen question to support-thredds just two months ago, and Ethan's reply is here:

http://mailman.unidata.ucar.edu/support/help/MailArchives/thredds/msg01334.html

Basically I guess the message is to not use the "reload" on THREDDS too many times and to periodically restart Tomcat?

But I'm still wondering whether setting -XX:MaxPermSize=256m in JAVA_OPTS (up from the default 64m) might help delay the problem (meaning I have to restart Tomcat less frequently). I guess I'll find out over the next few weeks...

-Rich


On Wed, Aug 26, 2009 at 11:27 AM, Rich Signell <rsignell@xxxxxxxx> wrote:
THREDDS folk,

I see that these is a TDS tutorial updated August 6 at:

http://www.unidata.ucar.edu/Projects/THREDDS/tech/tutorial/index.html

In the section on "Installing Java and Tomcat" I see that it's recommended to create a setenv.sh script in the <tomcat>/bin directory with these options:
JAVA_OPTS="-Xmx256m -Xms256m -server -Djava.awt.headless=true"







I've noticed that on our TDS4 installations, I often get a "PermGen" error which causes tomcat to hang. On this page:

http://confluence.atlassian.com/display/CONF29/Fix+Out+of+Memory+errors+by+Increasing+Available+Memory#FixOutofMemoryerrorsbyIncreasingAvailableMemory-PermGenSpaceParameters
I read:

Heap space memory errors will contain only a java.lang.OutOfMemoryError. If you get the error message: java.lang.OutOfMemoryError: PermGen space this means that you have exceeded Java's fixed 64Mb block for loading class files. You will need to add the argument -XX:MaxPermSize=256m to JAVA_OPTS, in addition to any argument you use to set the heap size.

PermGen Space Parameters

JAVA_OPTS="-Xms128m -Xmx1024m -XX:MaxPermSize=256m - Djava.awt.headless=true "


So I've set this my setenv.sh file for my Tomcat installation to read:

JAVA_OPTS="-Xms128m -Xmx1024m -server -XX:MaxPermSize=256m - Djava.awt.headless=true "

I have no idea yet whether this will help, as I just added the MaxPermSize parameter today. Anybody else have experience with PermGen problems running TDS4 and know if this should help or how to avoid in the first place?

Thanks,
Rich
--
Dr. Richard P. Signell   (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598




--
Dr. Richard P. Signell   (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598

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John Graybeal
Marine Metadata Interoperability Project: http://marinemetadata.org
graybeal@xxxxxxxxxxxxxxxxxx



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