This topic applies only on the z/OS operating system.

Running servers in 64-bit mode

You can configure a server running on the z/OS platform to use either 31-bit or 64-bit addressing. Whether a server is configured to use either 31-bit or 64-bit addressing does not affect its ability to interoperate or coexist with servers from this or earlier releases.

When you configure a server to run in 31-bit mode:
When you configure a server to run in 64-bit mode:

By default, newly configured servers run in 31-bit mode. You can convert some or all of your servers to run in 64-bit mode, based on the application requirements and virtual storage needs of each server. You might not need to switch some servers to 64-bit mode right away. However, because 31-bit mode support will be deprecated in a future release, you should plan to eventually convert all of your servers to 64-bit mode.

System requirements

To use the 64-bit mode server configuration:
  • You must be running your application servers on WebSphere Application Server Version 6.1.0.4 or higher on your z/OS platform.
  • If you are running z/OS Version 1 Release 6, the functions provided by z/OS PTFs UA29739 and UA30353 must be applied to your system.
  • The z/OS system data set SCLBDLL2 must be in the system link list or link pack area.
  • The 64-bit server module BBGCTL must be listed in the Program Properties Table, and the following lines must exist in an active SCHEDxx member on all z/OS systems on which you plan to run 64-bit servers:
  •  PPT PGMNAME(BBGCTL)       /* PROGRAM NAME BBGCTL      */ 
     KEY(2)                    /* PROTECTION KEY 2         */ 
     NOSWAP                    /* NON-SWAPPABLE            */ 
     PRIV                      /* PRIVILEGED               */ 
     CANCEL                    /* CANCEL ALLOWED           */ 
  • The data set SBBGLOAD, which contains 64-bit support modules, must be APF authorized.

    If the SBBGLOAD data set is not in the system link list or link pack area, then it must be in the cataloged procedure STEPLIB concatenation for each server which is to run in 64-bit mode, and specified in the STEPLIB variable in profile_root/bin/setupCmdLine.sh for each node containing a server running in 64-bit mode.

  • The AMODE=64 parameter must be included on the MVS START command when you start the server from the MVS console.
    Most V6.1.x cataloged procedures include the following JCL statements. These statements, minus the STEPLIB statement, determine whether the 31-bit server program (BBOCTL) or the 64-bit server program (BBGCTL) are invoked, based on the value you specify for the AMODE parameter on the MVS START command. If you are using a cataloged procedure that does not include these statements, use either the Customization Dialog or Profile Management Tool to regenerate the cataloged procedure, and then copy it to your system procedure library before converting the server to 64-bit mode.
    //STEP1    EXEC PGM=BBOOMTST,PARM='&AMODE.'             
    //STEPLIB  DD DISP=SHR,DSN=WAS.V61.SBBOLOAD             
    //TEST1    IF (STEP1.RC = 0) THEN                       
    //BBOCTL   EXEC PGM=BBOCTL,REGION=0M,TIME=MAXIMUM,      
    // PARM='TRAP(ON,NOSPIE),ENVAR("_EDC_UMASK_DFLT=007") / 
    //             &PARMS. REC=&REC'                        
    //BBOENV DD PATH='&ROOT/&ENV/was.env'                   
    // INCLUDE MEMBER=&Z                                     
    //           ELSE
    //BBGCTL   EXEC PGM=BBGCTL,REGION=0M,TIME=MAXIMUM,      
    // PARM='TRAP(ON,NOSPIE),ENVAR("_EDC_UMASK_DFLT=007") / 
    //             &PARMS. REC=&REC'                        
    //BBOENV DD PATH='&ROOT/&ENV/was.env'                   
    // INCLUDE MEMBER=&Z                                   
    //          ENDIF  
    Important: If the AMODE parameter is omitted or set to AMODE=31 on the MVS START command, the 31-bit server program is used. If AMODE=64 is specified on the MVS START command, then the 64-bit server program is used. The server program used must match the internal configuration setting for the server. If f it does not match, the server terminates with one of the following error messages:
    BBOO0329E THE SERVER IS CONFIGURED FOR 64-BIT MODE AND CANNOT BE STARTED IN 31-BIT MODE. 
       START THE SERVER IN 64-BIT MODE.
    
    BBOO0330E THE SERVER IS CONFIGURED FOR 31-BIT MODE AND CANNOT BE STARTED IN 64-BIT MODE. 
       START THE SERVER IN 31-BIT MODE.

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.

Important: Make sure that your system exits do not limit the address space size for 64-bit servers inappopriately.

Running servers in 64-bit mode requires additional auxiliary storage (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. You should 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

Application requirements

Before converting a server to 64-bit mode, make sure that you upgrade any of your custom DLLs, or connectors that use DLLs, to 64-bit versions.

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 the server is running in and load the correct 31-bit or 64-bit DLL to back native methods.

An application containing a 31-bit native module called under a 64-bit runtime or an application containing a 64-bit native module called in a 31-bit runtime will probably abend.

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.

Running an application server in 64-bit mode

You can use a stand-alone application server, or a managed application server in a Network Deployment cell, that is running in 64-bit mode, to run applications that are too large to run on a server that is configured for 31-bit mode. You can also configure this application server to use a larger JVM heap to accommodate larger amounts of data, or to process the same amount of data with less server overhead required for garbage collection.

Before converting an application server from 31-bit to 64-bit mode, verify that:
  • Your system meets the requirements specified in the Systems requirements section.
  • The application server's cataloged procedures include logic to invoke the 31-bit or 64-bit server program.
  • SBBGLOAD is either in the system link list or link pack area, or in both the STEPLIB concatenation in the server's cataloged procedures, and the profile_root/bin/setupCmdLine.sh file.
  • All applications that you plan to run on this application server are updated to use 64-bit native code and DLLs.
  • The fix for APAR PK35740 is applied to your system, if the application server you are converting connects to MQ in client mode (TCP/IP mode).

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 the AMODE=64 parameter is included on the command. For example:
S BBO6ACR,JOBNAME=BBOS001,ENV=PLEXA.SYS2.BBOS001,AMODE=64

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.

Running a deployment manager in 64-bit mode

A deployment manager that is running in 64-bit mode can handle larger applications than a deployment manager that is running in 31-bit mode. This capability is important for applications that use stack products or WebSphere Application Server feature packs.

Before converting a deployment manager from 31-bit to 64-bit mode:
  • Verify that your system meets the requirements specified in the Systems requirements section.
  • Verify that the deployment manager's cataloged procedures include logic to invoke the 31-bit or 64-bit server program,
  • Verify that SBBGLOAD is either in the system link list or link pack area, or in both the STEPLIB concatenation in the deployment manager's cataloged procedures, and the profile_root/bin/setupCmdLine.sh file.
  • Verify that all applications that you plan to run on the deployment manager are updated to use 64-bit native code and DLLs.

To convert a deployment manager 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 the deployment manager, 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 the deployment manager, 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 the AMODE=64 parameter is included on the command. For example:
S BBO6DCR,JOBNAME=BBODMGR,ENV=PLEXA.PLEXA.BBODMGR,AMODE=64

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.

Running other types of servers in 64-bit mode

You can use the same basic procedure to convert other types of servers, such as node agents and proxy servers, to 64-bit mode. However, these other types of servers generally do not derive any benefits from running in 64-bit mode.




Related tasks
Managing application servers
Related reference
Java virtual machine settings
Related information
z/OS Publications
64-bit Addressing Support
C/C++ Code Considerations With 64-bit WebSphere Application Server for z/OS
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Last updated: Feb 19, 2011 5:25:36 AM CST
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