Note 716604 - Access to Sun J2SE and recommended J2SE options

Summary

Symptom

Recommended Memory and VM Settings for SUN VMs for upgrading and installing WebAS 640/700 JavaEngine

Other terms

Out of Memory Permsize heap access download version option portal vm SUN

Reason and Prerequisites

During Upgrade to SP4 or higher different memory and VM settings are needed than during installation time of WebAS 640 Java. It is necessary to adapt these settings before starting the upgrade procedure. A minimum J2SE version is needed for upgrade and installation as well.

Solution

This note applies to the following platforms:
Solaris SPARC 32 Bit + 64 Bit and x86 (64 Bit)
Linux 32 Bit + 64 Bit (Itanium)
Windows 32 Bit + 64 Bit (x86 and Itanium)
Remark: AMD64 and x86 (64bit) means the same.

Recommended J2SE version:
Currently, we recommend SUN J2SE 1.4.2_27 for WebAS 640/700 JavaEngine on the platforms listed above.

Support for SUN J2SE 1.4.2
SAP and Sun did close an agreement to enable customers to continue using and receiving support for SUN J2SE 1.4.2 beyond the regular support period, which ended at October 2008 (for details see note 1230512).

Access to appropriate Sun J2SE version:
With Java SE for Business, SUN offers revisions for patch releases (e.g. 1.4.2_19 b07, 1.4.2_19 b08, ...), which means that collections of fixes are built in. A series of SAP-specific tests is conducted with each patch release (1.4.2_xy). If this was done for each revision, the effort would be multiplied. Therefore, the tests are applied to the initial patch release (1.4.2_xy), and only if severe errors occur, we will consider the revisions. This means that if not stated otherwise, the latest SUN J2SE 1.4.2 patch release is recommended. Exceptions will be reported below. Do not use J2SE 5.0.

There are two download pages, from which you could get the SDK.

First, there is a download page solely for SAP customers:

    http://www.sun.com/software/javaforbusiness/sap_download.jsp

It replaces the former page
    http://java.sun.com/j2se/1.4.2/SAPsite/download.html.
The new page contains J2SE 5.0 patch releases too, which are needed by some SAP applications. But for WebAS 6.40/700 Java there is still only J2SE 1.4.2 allowed.

You find on this page only patch releases and revisions recommended by SAP.

Second, for customers, who have signed a Java SE for Business contract themselves, SUN provides the following new download page for general released platforms:

     http://www.sun.com/software/javaseforbusiness/getit_download.jsp

Here you find the latest patch releases and all revisions.

The JCE policy files can also be downloaded now from

     http://www.sun.com/software/javaforbusiness/sap_download.jsp

Alternatively, you can use

     http://java.sun.com/products/archive

Choose version 1.4.2 of Java Cryptography Extension.

Important notes for special SUN J2SE versions:
Applying 1.4.2_24 b06 on server side and above solves the SPNego problem caused by Microsoft's Internet Explorer patch KB974455 (see SAP note 1397872).

Starting with 1.4.2_19 b07, the massive stack overflow problems are solved, that occur on Windows with 1.4.2_17 b12 and higher, 1.4.2_18 and earlier versions of 1.4.2_19 and 1.4.2_20 up to revision b03 if -XX:CompilerThreadStackSize is not set. Therefore do not use these versions (at least not on Windows) without this parameter. In the meantime the parameter is recommended anyway to avoid other rare cases of stack overflows of the compiler threads (see below).

With 1.4.2_14 - 1.4.2_17 you get an exception using Kerberos authentication with WebAS Java (see note 1057474). The problem is solved with 1.4.2_18 and higher, but as mentioned above, 1.4.2_18 should not be used. SAP has provided a workaround (see note 994791) if 1.4.2_14 - 1.4.2_17 is still in use.

There was a problem detected with the SAP startup framework of the WebAS Java in combination with SUN J2SE 1.4.2_13 on Linux x86 (32 Bit) and Linux Itanium (64 Bit). Please pay attention to note 1009962 (even if you use a higher version than 1.4.2_13).

With 1.4.2_11 the Java Systemcopy is much slower than with 1.4.2_12. Therefore at least 1.4.2_12 is recommended for the Java Systemcopy. See note 926085 for more information about the Java Systemcopy.

In 2007 there will be changes of the daylight saving time (DST) in US and Canada. The US change is handled correctly starting with 1.4.2_11, for Canada you need at least 1.4.2_13 (as described above you have to consider note 1009962 if you are running on Linux; because the SPs, which includes the fix are not released when DST starts in Canada you could also consider to use SUN's tzupdater tool
(see http://java.sun.com/javase/tzupdater_README.html); it covers Canadian timezones too). It's possible to use the newest version of tzupdater with older J2SE versions.

Operating system requirements
Please make sure that you have installed the lastest required operating system patches. On Windows 2003 Server, please make sure you have installed Microsoft Hotfix 841176 (if required). Please go to

         http://support.microsoft.com/?id=841176

for further information on whether the hotfix is required for your platform and on how to obtain it. The hotfix will be part of Windows Server 2003 Service Pack 1 when it will become available.

Minimum Java options for 6.40/7.00 SAP systems:
For 6.40:

For the "Java options:" the following minimal values are required for each ServerID:

-XX:PermSize=192m
-XX:MaxPermSize=192m

Please be aware of the fact that more permanent space is needed if additional applications are deployed or the complexity of the applications (roughly speaking the number of classes) grows.

For 7.0:

-XX:PermSize=256m
-XX:MaxPermSize=256m

Note: increasing of the heap size or permanent space on 32 bit systems (especially Windows) one should take into account limitations of the virtual address space, see notes 664607 and 736462.

For 6.40/7.00:

For the heapsize and the size of the new generation please take care of the recommendations of note 723909.

For Windows (ia64 and x86 (64Bit)) and Linux/ia64 (Itanium) platforms set the stack size to at least 2MB for each serverID, the dispatcher and the Java based tools:

-Xss2m

Additionally, increase the stack size of the JIT compiler threads at least on the server nodes of the J2EE Engine to 4MB on these platforms with following parameter (effective on Windows starting with 1.4.2_17 b12 resp. 1.4.2_18):

-XX:CompilerThreadStackSize=4096


Garbage Collector options for UltraSPARC T1 and T2 processors
In contrast to the information given in sections 7.1 and 7.2 of SAP Note 723909, for machines with UltraSPARC T1 and T2 processors, SUN recommends the following VM settings for garbage collection (on the server and the dispatcher):

-XX:+UseConcMarkSweepGC
-XX:+CMSPermGenSweepingEnabled
-XX:+CMSClassUnloadingEnabled
-XX:CMSInitiatingOccupancyFraction=60
-XX:+UseCMSInitiatingOccupancyOnly
-XX:ParallelGCThreads=<number of cores>
-XX:+UseParNewGC