When you create a new application server, it is automatically
configured to run in 64-bit mode. You can deselect the Run in 64
bit JVM mode setting if you need to run the server in 31-bit mode.
Whenever possible, however, leave your servers configured to run in
64-bit mode because support for running servers in 31-bit mode is
deprecated. If you have any servers, that you migrated from a previous
version of the product, that are running in 31-bit mode, consider
reconfiguring them to run in 64-bit mode.
Deprecated feature: Because support for running
a server in 31-bit mode is deprecated, whenever you start a server
that is configured to run in 31-bit mode, you receive the following
message in your system log, where
server_name is the name of
the server that is running in 31-bit mode:
BBOO0340W: 31-BIT MODE IS DEPRECATED FOR THE APPLICATION SERVER RUNNING ON THE Z/OS OPERATING SYSTEM.
CONSIDER USING 64-BIT MODE FOR server_name AS AN ALTERNATIVE.
depfeat
When a server runs in 31-bit mode, the following conditions exist:
- Each server address space can access a maximum of 2 gigabytes
of virtual memory.
- The 31-bit JVM, that is located in the app_server_root/java directory,
is used for the server.
When a server runs in 64-bit mode, the following conditions exist:
- Each server address space can access a maximum of 16 exabytes
(16 thousand million gigabytes) of virtual memory.
- The 64-bit JVM, that is located in the app_server_root/java64 directory,
is used for the server.
System requirements
Before starting to use
a server that is configured to run in 64-bit mode, note that:
- The AMODE parameter can be used to specify a particular addressing
mode, either 31-bit or 64-bit, for the server. This parameter can
also be set to a value of 00, which indicates
that the server is to use the configured addressing mode. In the generated
procedures, 00 is the default value for the AMODE parameter.
If
you convert a 31-bit server to the 64-bit addressing mode, make sure
that your automation does not specify AMODE=31 on the MVS START command.
If a server is started with an AMODE value that does not match the
configured addressing mode, the server does not start.
Avoid trouble: If the AMODE parameter is omitted,
or set to 00 on the MVS START command, then the server starts in the
currently configured addressing mode. If any other AMODE parameter
is specified, that parameter must match the currently configured addressing
mode. If the parameter does not match the currently configured addressing
mode, the server terminates with one of the following error messages:
gotcha
BBOO0336E START OF WEBSPHERE FOR Z/OS PROCESS FAILED BECAUSE INPUT
AMODE 31 DOES NOT MATCH CONFIGURED AMODE 64
BBOO0336E START OF WEBSPHERE FOR Z/OS PROCESS FAILED BECAUSE INPUT
AMODE 64 DOES NOT MATCH CONFIGURED AMODE 31
- The REGION parameter on the JCL JOB or EXEC statement, and the
MEMLIMIT parameter on the JCL JOB or EXEC statement, or in the SMFPRMxx
parmlib member, determines the amount of virtual storage that a particular
server can obtain. If you do not specify REGION=0M in the server
cataloged procedure, you must use the MEMLIMIT parameter to set a
virtual storage limit larger than the 2 gigabyte limit associated
with 31-bit mode.
Avoid trouble: Make sure that
your system exits do not limit the address space size for 64-bit servers
inappropriately.
gotcha
- Running servers in 64-bit mode requires additional auxiliary storage,
in the form of either expanded storage or page data set space. Before
running servers in 64-bit mode, review your page data set allocations
for each z/OS target system, and add additional page data set space
as needed. Also monitor paging and page data set utilization to ensure
that the allocated auxiliary storage is sufficient.
For more information, see the following z/OS publications:
- MVS™ Initialization and Tuning Reference,
SA22-7592
- MVS Programming: Extended Addressability Guide,
SA22-7614
Converting a migrated server to run in 64-bit mode
Before
converting an application server from 31-bit to 64-bit mode, complete
the following actions:
- Verify that your system meets the requirements specified in the
Systems requirements section.
- Verify that all applications that you plan to run on this application
server are updated to use 64-bit native code and DLLs.
The DLLs
and other native code that your applications call must match the addressing
mode of the server on which the applications are running. If you convert
an existing application server from 31-bit mode to 64-bit mode, you
must change any Java applications containing native
code, for example, C++ or Cobol, that you plan to run on the converted
server, to run in 64-bit mode. Java applications can use the com.ibm.vm.bitmode
Java property to determine the mode in which the server is running,
and then load the correct 31-bit or 64-bit DLL to the native code.
An
abend might occur if a server that is running in 64-bit mode tries
to invoke an application that contains a 31-bit native module. Similarly,
An abend might occur if a server that is running in 31-bit mode tries
to invoke an application that contains a 64-bit native module.
For
more information about converting language-environment (LE) applications
to run in 64-bit mode, see the z/OS publication Language
Environment Programming Guide for 64-bit Virtual Addressing Mode,
SA22-7569.
To convert an application server from 31-bit mode to 64-bit
mode, in the administrative console select the Run in 64 bit JVM
mode option on the configuration settings page for that application
server, and change the minimum and maximum JVM heap sizes to values
that are appropriate for a 64-bit process. Similarly to convert an
application server from 64-bit mode to 31-bit mode, deselect the Run
in 64 bit JVM mode option on the configuration settings page for
that application server, and change the minimum and maximum JVM heap
sizes to values that are appropriate for a 31-bit process.
If
you use the MVS START command to start a 64-bit server, make sure
that the AMODE parameter is set to 00 or 64, or is allowed to default
to 00, on the START command. For example, you might issue one of the
following commands:
S BBO7ACR,JOBNAME=BBOS001,ENV=BBOBASE.BBONODE.BBOS001,AMODE=64
S
BBO7ACR,JOBNAME=BBOS001,ENV=BBOBASE.BBONODE.BBOS001
The
startServer.sh command, and the administrative console, automatically
add the AMODE=64 parameter when they are used to start a 64-bit application
server.
Converting a migrated deployment manager to run in
64-bit mode
Before converting a deployment manager from
31-bit to 64-bit mode, complete the following actions:
- Verify that your system meets the requirements specified in the
Systems requirements section.
- Verify that all applications that you plan to run on the deployment
manager are updated to use 64-bit native code and DLLs.
The DLLs
and other native code that your applications call must match the addressing
mode of the server on which the applications are running. If you convert
an existing application server from 31-bit mode to 64-bit mode, you
must change any Java applications containing native code, for example,
C++ or Cobol, that you plan to run on the converted server, to run
in 64-bit mode. Java applications can use the com.ibm.vm.bitmode Java
property to determine the mode in which the server is running, and
then load the correct 31-bit or 64-bit DLL to the native code.
An
abend might occur if a server that is running in 64-bit mode tries
to invoke an application that contains a 31-bit native module. Similarly,
An abend might occur if a server that is running in 31-bit mode tries
to invoke an application that contains a 64-bit native module.
For
more information about converting language-environment (LE) applications
to run in 64-bit mode, see the z/OS publication Language
Environment Programming Guide for 64-bit Virtual Addressing Mode,
SA22-7569.
To convert a deployment manager from 31-bit mode to 64-bit
mode, go to Servers > Server types > WebSphere application
servers > server_name in the administrative
console and select the Run in 64 bit JVM mode option on the
configuration settings page for the deployment manager as well as
change the minimum and maximum JVM heap sizes to values that are appropriate
for a 64-bit process.
If you use the MVS START command to start
a 64-bit deployment manager, make sure that the AMODE parameter is
set to 00 or 64, or is allowed to default to 00, on the START command.
For example, you might issue one of the following commands:
S BBO7DCR,JOBNAME=BBODMGR,ENV=PLEXA.PLEXABBOCELL.BBODMGR.BBODMGR,AMODE=64
S BBO7DCR,JOBNAME=BBODMGR,ENV=BBOCELL.BBODMGR.BBODMGR
The
startServer.sh command and the administrative console automatically
add the AMODE=64 parameter when they are used to start a 64-bit deployment
manager.
Converting a server to run in 31-bit mode
Before
converting a server from 64-bit to 31-bit mode, verify that all applications
that you plan to run on the server use 31-bit native code and DLLs.
To
convert a server from 64-bit mode to 31-bit mode, complete the following
actions:
- Start the server.
The server tells you what mode it is in when
it starts:
BBOO0309I CONTROL PROCESS BBOBASE/BBONODE/BBOC001/BBOS001 IS EXECUTING IN 64-BIT ADDRESSING MODE
- Go to Servers > Server types > WebSphere application
servers > server_name in the administrative
console.
- Deselect the Run in 64 bit JVM mode option on the configuration
settings page for the server.
- Restart the server.
Now, the following messages appear on the
console and in the server job log:
09.31.42 STC00104 BBOO0309I CONTROL PROCESS BBOBASE/BBONODE/BBOC001/BBOS001 IS EXECUTING
IN 31-BIT ADDRESSING MODE.
09.31.42 STC00104 BBOO0340W 31-BIT MODE IS DEPRECATED FROM THE APPLICATION SERVER ON THE
Z/OS OPERATING SYSTEM. CONSIDER USING 64-BIT MODE FOR BBOS001 AS AN ALTERNATIVE.