SAP Basis Tech Supports

Symptom
Recommended Settings for the IBM 1.4.2 JVM (J9) for SAP NetWeaver 2004 SP22 and above or NetWeaver 7.0 (2004s) SP15 and above on Linux on System z
Other terms
Java Virtual Machine, JDK, SDK, J9, PI, Enterprise Portal, z/Linux, zLinux, Linux390, Linux for zSeries
Reason and Prerequisites
For SAP NetWeaver 2004 SP22 or above or NetWeaver 7.0 (2004s) SP15 and above the new IBM 1.4.2 Hybrid JVM with J9 technology will be used on zLinux.
OS level:
An operating system which is described in SAP Note 81737.
JCE unrestricted policy files:
New (latest) files are required.
SAP Note 1306760 has to be implemented
Introducing missing iiop functionality for IBM 1.4.2 SR13 JDK
General Java VM settings for J2EE 6.40/7.0:
see SAP note 723909.
Solution
1. Make sure that you have installed the required SDK:
You have to download the SDK 1.4.2 64-bit ServiceRelease 13 from the download site “IBM Java for ISVs”:
https://www14.software.ibm.com/webapp/iwm/web/preLogin.do?lang=en_US&source=swg-ibmjavaisv
The access key for SAP is AQ2QQK45DQ
First you have to sign in with your IBM user ID .
If you do not yet have an IBM user ID, please register at the IBM registration site:
https://www.ibm.com/account/profile/us?page=reg
If the links don’t work, please check for a superfluous space within the URL string.
After login go to paragraph “IBM SDK for Linux on 64-bit zSeries ” and download:
the rpm format “IBMJava2-142-z64-SDK-1.4.2-13.0.s390x.rpm” or
the tgz format of the SDK “IBMJava2-SDK-1.4.2-13.0.s390x.tgz”.
You can verify this requirement by running ‘java -fullversion’. The version and build information in the output text must be: “J2RE 1.4.2 IBM build cxz64142- 20090307 (SR13)”.
The version information (java -Xj9 -version) if you run the J9 technology (-Xj9) will show a slightly different version information:
“IBM J9 VM (build 2.3, J2RE 1.4.2 IBM J9 2.3 Linux s390x-64 j9xz64142- 20090310 (JIT enabled)”. This version information can be found in the log and trace files too.
After the SDK upgrade you have to install the “Unlimited Strength Jurisdiction Policy Files” manually again, because these are overwritten during the SDK upgrade (see SAP note 754699, 739043).
For SR13 new (the latest) JCE Policy Files are required!
2. Prepare the system to run with J9 technology
To use the new J9 technology for all SAP related applications are running under the <SID>adm user account you have to add the following environment variable:
IBM_JAVA_OPTIONS=-Xj9
Please add the environment variable to the <SID>adm user environment in /home/<SID>adm/ to the file “.j2eeenv_<hostname>.csh”
setenv IBM_JAVA_OPTIONS “-Xj9″
If IBM_JAVA_OPTIONS is already set e.g.
setenv IBM_JAVA_OPTIONS “-Xmx256M”
replace it with:
setenv IBM_JAVA_OPTIONS “-Xmx256M -Xj9″
Add to the file “.j2eeenv_<hostname>.sh”
IBM_JAVA_OPTIONS=”-Xj9″; export IBM_JAVA_OPTIONS
If IBM_JAVA_OPTIONS is already set e.g.
IBM_JAVA_OPTIONS=”-Xmx256M”; export IBM_JAVA_OPTIONS
replace it with:
IBM_JAVA_OPTIONS=”-Xmx256M -Xj9″; export IBM_JAVA_OPTIONS
Logoff and login again with the <SID>adm user and check if the environment is set (env command).
During a NetWeaver 2004 upgrade the <SID>adm user environment will be overwritten by the SAP installer. So please double check the environment and add the -Xj9 parameter again.
3. Prepare the J2EE to detect the new JDK
Delete the instance.properties.vmprop file in the /usr/sap/<SID>/<JCXX>|<DVEBMGSXX>/j2ee/cluster directory.
During the first J2EE startup this file will be recreated with the new JVM version information.
4. Configure the J2EE (Dispatcher and Server) JVM parameter set
Start the configtool
(/usr/sap/<SID>/<JCXX>|<DVEBMGSXX>/j2ee/configtool/configtool.sh)
Do not remove any application specific parameters which starts with a “-D”, which are described in SAP note 723909.
Remove the previous JVM specific parameters like:
-Xloratio0.3
-Xparroot
-Xconcurrentlevel6
-Xconcurrentbackground4
-XSoftRefThreshold0
-Xconmeter2
-Xk<number of classes>
-Xp<initial cluster size>,<overflow cluster size>
-verbose:Xgccon
Set the following JVM parameters for the dispatcher:
Max heap size (in MB): 200
-Xms200M
-Xj9
-Xgcpolicy:gencon
-Xmn70M
-Xthr:minimizeUserCPU
-verbose:gc
-Xdump:system:events=systhrow,filter=java/lang/OutOfMemoryError,request=exclusive+prepwalk
Set the following JVM parameters for all server nodes:
Max heap size (in MB): 2048
-Xms2048M
-Xj9
-Xgcpolicy:gencon
-Xmn600M
-verbose:gc
-Xdisableexplicitgc
-Xsoftrefthreshold1
-Xthr:minimizeUserCPU
-Xdump:system:events=systhrow,filter=java/lang/OutOfMemoryError,request=exclusive+prepwalk
For SAP Portals please implement SAP note 905211 (PCD Cache Optimizer Tuning) to avoid performance degradation due to soft reference handling by the GC (-Xsoftrefthreshold1).
Please implement SAP Note 1306760 to avoid ORB/IIOP problems.
With the parameter -Xdump:system:events=systhrow,filter=java/lang/OutOfMemoryError,request=exclusive+prepwalk
the JVM will write a system dump in case of an OOM. This can be used for the analysis with the Eclipse Memory Analyzer. For more information see SAP note 1336952.