Facilities, Sysplex, Components and assumptions

GDPS is discussed in a white paper available at ibm.com/

Continuous Availability Recommended Conﬁguration for Parallel

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

Sysplex

	IC
z/OS	ICF

Dedicated (External)

Coupling Facility

z890 or

z990 with CFs only, z900 Model 100 9674, 9672 R06, or z800 Model 0CF

Internal Coupling

Facility

z/OS

enable that any exchanges of timestamped information between systems in a sysplex involving the Coupling Facil- ity observe the correct time ordering, time stamps are now included in the message-transfer protocol between the sys- tems and the Coupling Facility. Therefore, when a Coupling Facility is conﬁ gured as an ICF on any z890, z990 or z900 Models 2C1 through 216, the Coupling Facility will require connectivity to the same 9037 Sysplex Timer that the sys- tems in its Parallel Sysplex cluster are using for time syn- chronization. If the ICF is on the same server as a member of its Parallel Sysplex environment, no additional connectiv- ity is required, since the server already has connectivity to the Sysplex Timer. However, when an ICF is conﬁ gured on any z890, 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

Sysplex Timers

ESCON/FICON Express Channels

Note: z890/z990 will attach to 9037-001 or 9037-002. Ser- vice for 9037-001 discontinued end of 2003.

Components and assumptions

• Two Coupling Facilities; at least one external or else

using System-Managed CF Structure Duplexing

• Two Sysplex Timers

• Two z/OS or OS/390 servers with redundant backup

capacity

• Two links from each CF to each image

• Two hardware management consoles

• Two ESCON or FICON Directors with cross-connected

disks

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

CF01

ICF

Non-Sysplex z/OS LPARs

	12
11	12	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/		ISC-
					3
	Timer
	Timer		IBM ^z900
	Sysplexto				or z890/z990
					or z890/z990
	Connection					LPARs
			z/OS			Sysplex
			z/OS			Sysplex
	New

• Dual electrical power grids
• Cloned OS/390 images, latest available software levels
•	Automation capabilities for recovery/restart
•	Critical data on RAID and/or mirrored disks