Normal operations in a mixed complex

Once the complex is built, it requires little, if any, operator intervention unless a problem disrupts ring processing or the ring requires reconfiguration for some other reason. If a problem occurs that is not related to ring processing, either global resource serialization or some other system component will detect the problem and issue messages that describe it before the operator could notice it.

For example, some of the error messages that global resource serialization issues indicate damage to resources or to the resource control blocks, rather than a problem with ring processing. These messages are ISG031E, ISG032E, ISG033E, ISG034E and ISG035E. The problem that causes any of these messages can also cause the job requesting the resource to terminate abnormally. If the damage is extensive, the problem can cause multiple jobs to terminate abnormally, requiring the system to IPL again to restore the control blocks. This problem is, of course, only one example of a problem not directly related to ring processing that can force a system in the ring to IPL again.

During normal processing, as well as during recovery from a ring disruption, operators use system commands to monitor and control global resource serialization. The system commands related to ring processing are:

DISPLAY GRS, which displays the status of each system in the complex. D GRS is the operator's primary way of checking ring processing and determining the source of problems. See Displaying ring status.
VARY GRS with the QUIESCE operand, which allows the operator to remove a system from the ring. See Quiescing a system.
VARY GRS with the PURGE operand, which allows the operator to remove a system from the complex. See Purging a system.
VARY GRS with the RESTART operand, which allows the operator to restart a quiesced system or an inactive system. See Restarting a system.
VARY devnum, which allows the operator to bring a link online or take a link offline. See Controlling CTC links.
VARY CTC,OFFLINE,FORCE, which permanently removes a CTC from use by global resource serialization and releases it for other uses. See Migrating an existing complex into a sysplex for an example of how and when to use this command.

It is a good practice, whenever possible, to issue all VARY commands for the ring from the same system; this practice simplifies operations procedures, especially during recovery.

If your mixed complex contains systems in an XCF multisystem sysplex, additional system commands for those systems related to ring processing are:

VARY XCF,sysname,OFFLINE, which removes a system from the sysplex. (Any action that removes a system from the sysplex also removes it from the global resource serialization complex.) See z/OS MVS Setting Up a Sysplex for more information.