SAP Basis Tech Supports

Symptom
Recommended Settings for the IBM JVM (J9) for SAP NetWeaver 7.0 (2004s) Application Server Java SR2 and newer on AIX fornew installtions only.
Other terms
Java Virtual Machine, JDK, SDK, J9, XI, Enterprise Portal,
Reason and Prerequisites
Starting with SAP NetWeaver 7.0 (2004s) SR2 the new IBM JVM 1.4.2 with J9 technology will be used on AIX fornew installations(see SAP note 1039948).
OS level:
AIX 5.2 + APAR IY84258
This APAR will be in 5200-08-CSP or newer.
AIX 5.3 + APAR IY82426 and IY89080
This APAR will be in 5300-05 SP1 or newer.
AIX 6.1 SP1
JCE unrestricted policy files:
New (latest) files are required with 1.4.2 SR12 and newer!
General Java VM settings for J2EE 6.40/7.0:
see SAP note 723909.
SAP NetWeaver minimum patch level to use SR13 and newer:
see SAP note 1306760.
Wily Introscope:
Wily Introscope agent with version 7.1 patch 1 and above (SAP note
1015184).
Solution
Make sure that you have installed the required SDK:
Prerequisite to install SR13 is the implementation of SAP note
1306760 (Introducing missing iiop functionality for IBM JDK 1.4.2
SR13).
You have to download the SDK 1.4.2 64-bit ServiceRelease 13 from the
new download site “IBM Java for ISVs”:
https://www14.software.ibm.com/webapp/iwm/web/preLogin.do?lang=en_US
&source=swg-ibmjavaisv
You need an IBM ID (developerWorks or PartnerWorld) to login. The
access key for the entitlement is AQ2QQK45DQ.

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 AIX 5L for PowerPC (64 bit JVM) build caix64142-20090307 (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 AIX ppc64-64 j9ap64142-20090310 (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 SR12 and newer, new (the latest) JCE Policy Files are required!

If you are using Wily Introscope you will need Wily Introscope agent with version 7.1 patch 1 and above (SAP note 1015184).
Verify that the <SID>adm user has the right environment settings. This should be automatically set during the SAP NetWeaver 7.0 (2004s) SR2 installation.
To use the new J9 technology for all SAP related applications are
running under the <SID>adm user account please check if the following environment variable is set:
IBM_JAVA_OPTIONS=-Xj9
Please check if the environment variable for the <SID>adm user
is set in /home/<SID>adm/.j2eeenv_<hostname>.csh
setenv IBM_JAVA_OPTIONS “-Xmx256M -Xj9″
Check if the environment variable in the file .j2eeenv_<hostname>.sh is set too.
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).
Currently we recommend the following settings for the J2EE dispatcher and server(s) (to be set with the configtool):
Set the following JVM parameters for the dispatcher:
Max heap size (in MB): 200
-Xms200M
-Xmn70M
-Xgcpolicy:gencon
-verbose:gc
-Xj9
-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
-Xmn1000M
-Xgcpolicy:gencon
-verbose:gc
-Xj9
-Xdisableexplicitgc
-Djava.net.preferIPv4Stack=true
-Xdump:system:events=systhrow,filter=java/lang/OutOfMemoryError,request=exclusive+prepwalk
-Xsoftrefthreshold1

Please implement SAP note 905211 to avoid performance degradation
(PCD) due to changed soft reference handling by the GC
(-Xsoftrefthreshold).
The parameter change from -Xsoftrefthreshold0 to -Xsoftrefthreshold1 is recommended for SR12 or newer. This parameter change will reduce the number of loaded classes/classloader. Main results are shorter class unloading times and reduced GC pause times.
In addition there will be a significant native memory footprint reduction with SR12. This effect is covered in SR13 already.
The parameter -Djava.net.preferIPv4Stack=true can avoid startup
problems in a network environment that is not configured to support
IPv6. For more information see SAP note 861333 and 1137949.
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 1259465.

Do not remove any application specific parameters which starts with
a “-D”, which are described in SAP note 723909.