IBM z/OS manual Parallel Sysplex, Facilities

Automatic Enablement of CBU for Geographically Dispersed

Parallel Sysplex

The intent of the GDPS (CBU) is to enable automatic man- agement of the reserved PUs provided by the CBU feature in the event of a processor failure and/or a site failure.

Upon detection of a site failure, GDPS will dynamically add PUs to the confi guration in the takeover site to restore processing power for mission-critical production work- loads. GDPS-CBU management helps to minimize manual customer intervention and the potential for errors, thereby helping to reduce the outage time for critical workloads from hours to minutes. Similarly, GDPS-CBU management can also automate the process of dynamically returning the reserved CPs when the temporary period has expired.

z900 Models 2C1 through 216, the Coupling Facility will require connectivity to the same 9037 Sysplex Timer that the systems in its Parallel Sysplex cluster are using for time synchronization. If the ICF is on the same server as a member of its Parallel Sysplex environment, no additional connectivity is required, since the server already has connectivity to the Sysplex Timer. However, when an ICF is confi gured on any z990 or z900 Models 2C1 through 216 which do not host any systems in the same Parallel Sysplex cluster, it is necessary to attach the server to the 9037 Sysplex Timer.

z900 Turbo or z890/z990 Model with ICF and non-Parallel Sysplex LPARs

GDPS is discussed in a white paper available at ibm.com/ server/eserver/zseries/pso/library.html. GDPS is a service offering of IBM Global Services. For IBM Installation Ser- vices for GDPS, refer to the IBM Web site.

Message Time Ordering (Sysplex Timer Connectivity to Coupling

Facilities)

As processor and Coupling Facility link technologies have improved over the years, the requirement for time synchro- nization tolerance between systems in a Parallel Sysplex environment has become ever more rigorous. In order

to ensure that any exchanges of timestamped informa- tion between systems in a sysplex involving the Coupling Facility observe the correct time ordering, time stamps are now included in the message-transfer protocol between the systems and the Coupling Facility. Therefore, when a Coupling Facility is confi gured as an ICF on any z990 or

			-3
			/ISC
	-4
		ICB
	-3/
		ICB
			Timer
IBM ^z900
			Sysplex
or z890/z990
Sysplex		z/OS
LPARs			to
		ICF	Connection
	IC
		CF02
			New

CF01

ICF

	z/OS
Non-Sysplex
LPARs

	12
11		1	11	12	1
10		2	10		2
9		3	9		3
8		4	8		4
7	6	5	7	6	5

ICB-
3		/	ICB-
		4/		I
				SC-
					3
	Timer
			IBM ^z900
	Sysplexto				or z890/z990
	Connection					LPARs
			z/OS			Sysplex
	New

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