REALLOCATE process

The REALLOCATE process provides a means to evaluate each allocated structure and to adjust as needed the location of structure instance(s) with a single operator command. Like POPULATECF, the primary usage is to populate a coupling facility that has been brought into use in a sysplex. Unlike POPULATECF, the REALLOCATE process can adjust the location of both simplex and duplexed structures. The advantage of the REALLOCATE process is that it uses structure allocation criteria to determine whether to initiate structure rebuild processing to move allocated instance(s) into coupling facilities listed in the preference list from either the active or pending CRM policy. If the structure instance(s) already reside in the "more suitable" coupling facility, the system will not initiate structure rebuild processing.

The XCF allocation algorithm builds a list of eligible CFs using the structure’s preference list and the state of the CF. Coupling facilities that are in maintenance mode, pending delete from the CFRM active policy, in cleanup, or failed are eliminated from the eligibility list. When a CF is in any of these states, it is considered less suitable. You can place a coupling facility in and out of maintenance mode using the SETXCF START MAINTMODE and SETXCF STOP MAINTMODE commands. See Coupling facility resource allocation “rules” and Sample procedure for coupling facility maintenance.

For example, assume that a coupling facility structure is duplexed with the old instance in the third CF listed in the preference list and the new instance in the first CF listed in the preference list. If evaluation using the structure allocation criteria determines that the "more suitable" location for the structure instances should have the old instance in the first CF listed and the new instance in the second CF listed, then the REALLOCATE process would take two steps to adjust the location by stopping duplexing keeping the new instance followed by reduplexing the structure. The result would have the old instance in the first CF listed in the preference list and the new instance in the second CF listed.

You can use the SETXCF START,REALLOCATE operator command to do the following:

Move structures out of a CF following a CFRM policy change that deletes/changes that CF (for example, in preparation for a CF upgrade).
Move structures out of a CF following placing the CF into maintenance mode.
Move structures back into a CF following a CFRM policy change that adds/restores the CF (for example, following a CF upgrade/add).
Move structures back into a CF following taking a CF out of maintenance mode.
Clean up pending CFRM policy changes that may have accumulated for whatever reason, even in the absence of any need for structure "relocation" per se.
Clean up simplex or duplexed structures that were allocated in or moved into the "wrong" CF(s), for whatever reason (for example, the "right" CF was inaccessible at the time of allocation).
Clean up duplexed structures that have primary and secondary "reversed" due to a prior condition which resulted in having duplexing stopped with KEEP=NEW and the structure reduplexed.

Note:

REALLOCATE processing may require that all systems have connectivity to all coupling facilities. End of change

Before starting a REALLOCATE process, you can use the DISPLAY XCF,REALLOCATE,TEST command to request information (through message IXC347I) about what can be expected from subsequent REALLOCATE processing.

You can use the DISPLAY XCF,REALLOCATE,REPORT command to request detailed information (through message IXC347I) about the most recent REALLOCATE process. If a REALLOCATE process ends with an exception condition, the system automatically issues the DISPLAY XCF,REALLOCATE,REPORT command internally.