IBM Support

Additional Support for System-Managed Cache Structure rebuilds

Troubleshooting


Problem

With PTF UA50926, a "System-Managed" rebuild of the SYSPLEX cache structure is now supported while AF address spaces are connected to the structure.

Symptom

Prior to UA50926, a System Managed rebuild of the cache structure could only be done when no AF address spaces were connected.

Resolving The Problem


Prerequisites:
In order to perform a system-managed rebuild while AF tasks are still connected to the cache structure, all tasks must have UA50926 applied. Additionally, the cache structure must be defined in the active coupling facility resource management (CFRM) policy with more than one coupling facility in its preference list.

Enabling the new startup option:
The customizer panels have been updated to include a YES/NO field for the new SYSTEM-MANAGED option. This translates into a startup parameter with the following syntax:

CACHE(STRNAME(KOG_RSV_POOL),SYSTEM-MANAGED(YES/NO))

The SYSTEM-MANAGED(YES) option supersedes the WRITE(CHANGED) option that was previously necessary for system-managed rebuild toleration.

The default is SYSTEM-MANAGED(YES).

If the option is in effect, the response from an “AF” command will contain the following line:
!AOP0151 OPTIONS IN EFFECT: CACHE(STRNAME(KOG_RSV_POOL),SYSTEM-MANAGED)

Existing structure content incompatibility:
If the existing content of the cache structure prevents the SYSTEM-MANAGED option from taking effect, the message !AOP3937 CACHE STRUCTURE SYSTEM-MANAGED OPTION IGNORED, EXISTING CONTENT IS INCOMPATIBLE will be produced at product startup. The likely cause of incompatible content is that the structure was initially allocated by an AF task that did not specify the WRITE(CHANGED) or SYSTEM-MANAGED options. If your structure has incompatible content there are a couple of options:

1) To preserve the contents of the “SYSPLEX” RSV pool there is a new sample REXX procedure called KOGSTRUT that will allow the backup and restoration of the “SYSPLEX” RSV pool. See the header section of KOGSTRUT in TKANSAM for more details of this process.

2) To discard the contents of the “SYSPLEX” RSV pool you can simply delete the structure. To delete it use the SETXCF FORCE,STR,STRNAME=XXXXXXXXX command while no AF tasks are connected to it (Use this command with caution! This option is not recommended for RSM users who are running in SYSPLEX mode).

Mixed levels and options:
It is possible for tasks with differing options to be connected to the same structure at the same time. They should all be able to access variables in the “SYSPLEX” RSV pool normally. However, any active connectors to the structure that don’t opt for a system-managed rebuild will prevent the rebuild from being performed.

The system-managed option is mutually exclusive with the user-managed duplexing rebuild that AF also permits. If you have a structure which has the DUPLEX(ALLOWED) attribute, it will not stop the system-managed rebuild from being performed. However, active connectors with differing options will prevent either type of rebuild from being performed.

Performing a Rebuild:
A system-managed rebuild of the cache structure can be initiated using the command:
SETXCF START,REBUILD,STRNAME=xxxxxxxxxx

Do not attempt this rebuild if the structure was created without the WRITE(CHANGED) or SYSTEM-MANAGED options.

[{"Product":{"code":"SSRJ25","label":"Tivoli OMEGACENTER Gateway on z\/OS"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Component":"--","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"3.4","Edition":"","Line of Business":{"code":"LOB35","label":"Mainframe SW"}},{"Product":{"code":"SSRMRD","label":"Tivoli AF\/OPERATOR on z\/OS"},"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Component":" ","Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"3.4","Edition":"","Line of Business":{"code":"LOB35","label":"Mainframe SW"}}]

Document Information

Modified date:
03 August 2018

UID

swg21433760