GRSCNFxx (global resource serialization configuration)

The contents of the GRSCNFxx parmlib member are used during system initialization to define the attributes of global resource serialization processing.

A global resource serialization complex consists of two or more systems connected by communication links. The systems in the complex use global resource serialization to serialize any shared resources such as controlling access to data sets on shared DASD volumes at the data set level rather than at the volume level. (For more information, see z/OS MVS Planning: Global Resource Serialization.)

The majority of GRSCNFxx parameters are specific to defining a global resource serialization ring complex. However, GRSQ is specific to star mode, and the following keywords are relevant for all modes, including GRS=NONE:
  • SYNCHRES
  • ENQMAXA
  • ENQMAXU
  • AUTHQLVL
  • MONITOR
To define a global resource serialization ring complex, use the GRSCNFxx parmlib member. GRSCNFxx contains a GRSDEF statement for each system. The statement identifies:
  • The name of the system in the complex, by means of the MATCHSYS parameter.
  • The CTC links assigned to the system, by means of the CTC parameter.
  • The minimum amount of time that the RSA-message is to spend in the system, by means of the RESMIL parameter.
  • Whether or not the system identified by the MATCHSYS keyword has the automatic restart capability, by means of the RESTART parameter.
  • Whether or not the system identified by the MATCHSYS keyword has the capability to automatically rejoin the complex, by means of the REJOIN parameter.
  • The maximum amount of time (the tolerance time interval) before global resource serialization will detect a timeout, by means of the TOLINT parameter.
  • The method to establish the global resource serialization ring acceleration function, by means of the ACCELSYS parameter.
  • The member of parmlib that contains the default global resource serialization component tracing options, by means of the CTRACE parameter.

There are three basic ways to use GRSCNFxx to define your complex:

  1. You can create one GRSCNFxx parmlib member that contains GRSDEF statements that define all of the systems in the complex. After creating the member, copy it to the parmlib on each system. As each system is initialized, it reads the GRSCNFxx member, locates its own GRSDEF statement, and uses the information in the statement during initialization.
  2. You can create a unique GRSCNFxx member for each system in the complex. The member consists of a GRSDEF statement for that particular system. You place the unique member in parmlib on that particular system, and that system uses the information it contains during initialization.
  3. If all systems in the global resource serialization complex will belong to the same sysplex, you can create one GRSCNFxx member that contains a single GRSDEF statement that defines consistent information for all systems. The IBM-supplied default member, GRSCNF00, can be used for this purpose.
Variations or combinations of these methods are, of course, possible. Which ever method you choose, GRSCNFxx provides information about the configuration of the complex that global resource serialization requires during initialization. Other information that global resource serialization requires comes from the following system parameters (in IEASYSxx):
  • GRS=
  • GRSCNF=
  • GRSRNL=
  • SYSNAME=

The GRS, GRSCNF, GRSRNL, and SYSNAME parameters can only be specified at IPL time, either in IEASYSxx or by the operator. They all remain in effect for the duration of the IPL. For specific details about how to specify any one of these parameters, see the description of the parameter provided in IEASYSxx (system parameter list).

During initialization processing for a system that is to join an existing complex, global resource serialization verifies that the information in GRSCNFxx is consistent with the existing complex. Even if a system is defined in a GRSCNFxx parmlib member and initialized with GRS=JOIN, it cannot join the complex unless either:
Parent topic: Members of SYS1.PARMLIB