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Increasing the heap memory in RTC tomcat application throws error. What is the right way to increase the memory?


aastha khatri (22619) | asked Apr 15 '20, 7:30 a.m.
Hi,
I am moving from server to VM. My server use to have 48gb RAM, our JVM memory parameters are
JAVA_OPTS="$JAVA_OPTS -Xmx25G"
JAVA_OPTS="$JAVA_OPTS -Xms10G"
JAVA_OPTS="$JAVA_OPTS -Xmn5G"
Now we are moving to VM having 200gb of RAM. So I want to increase the heap memory of JVM in RTC (serverstartup.sh). I am using tomcat.I tried to give following parameters
JAVA_OPTS="$JAVA_OPTS -Xmx50G"
JAVA_OPTS="$JAVA_OPTS -Xms25G"
JAVA_OPTS="$JAVA_OPTS -Xmn5G"
but I get error
JVMJ9GC028E Option too large: '-Xmx'
JVMJ9VM015W Initialization error for library j9gc24(2): Failed to initialize
Could not create the Java virtual machine.
 When I run free I get following output
[vm]# free -g
                    total        used        free      shared  buff/cache   available
Mem:            196          27          37           0         131         167
Swap:             0           0           0

Any idea why this error is thrown? What is the right way of increasing the memory ?

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Ralph Schoon (63.1k33646) | answered Apr 15 '20, 9:08 a.m.
FORUM ADMINISTRATOR / FORUM MODERATOR / JAZZ DEVELOPER
This question has most likely nothing to do with RTC, It is very likely related to the Java JVM. Do the following:
  1.  Open your trusted search engine
  2. Enter JVMJ9GC028E as a search parameter
  3. Go through the answers e.g. on Stackoverflow.
I am not a JVM expert, but some of the answers seem to make sense to me.

Comments
aastha khatri commented Apr 16 '20, 7:18 a.m.
Hi Ralph,
Thankyou so much for your proactive response as always.
I tried searching it on web, everywhere the general solution for this was that they observe this issue in 32bit JVM but moving to 64bit JVM solves the issue. I see that I am using 64bit JVM only. Strange part is I know other team which can simply increase the heap memory by modifying in serverstartup.sh of RTC application. But I am clueless why I am seeing this error inspite of large RAM , 64bit JVM.
Could you point me someone from JAZZ performance team , who could guide me here.
Thanks and stay safe!

Ralph Schoon commented Apr 16 '20, 8:04 a.m. | edited Apr 16 '20, 8:04 a.m.
FORUM ADMINISTRATOR / FORUM MODERATOR / JAZZ DEVELOPER
Hi,

I saw the hint towards the 32/64 bit as well.

I am not a Java JVM expert. If you use the IBM Java, you can open a support case against ELM. They would open an expert case with the IBM Java development team, if they don't have an answer. They will likely ask for more data.

Sorry, but that is the only answer I can provide.

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