IBM eServer zSeries 990 Technical Guide

166 IBM ^ zSeries 990 Technical Guide

For availability reasons, there should be:

򐂰 At least two coupling links between z/OS and/or OS/390 and Coupling Facility images

򐂰 At least two Coupling Facility images (not running on the same server)

򐂰 At least one stand-alone Coupling Facility (if using system-managed CF structure

duplexing or running with “Resource Sharing” only, then a stand-alone Coupling Facility is

not mandatory)

򐂰 At least two Coupling Facility images are required for system-managed CF structure

duplexing.

7.2.5 Coupling Facility Resource Manager (CFRM) policy considerations

Because the z990 is capable of having greater than 15 logical partitions, there is a change in

the usage of the PARTITION keyword when defining the CFRM policy via the administration

utility. Support has been added to allow for two digits in the keyword PARTITION(nn). The

meaning of keyword also depends upon if the CF location resides on a z990 or non-z990 (see

Figure 7-3 for more details).

If the CF LPAR ID on the z990 is equal or less than x' F’, then z/OS compatibility support is

not required on z/OS partitions running on non-z990 processors (see 6.2.1, “Compatibility

Support for z/OS” on page 134).

Figure 7-3 CFRM Policy changes

7.2.6 ICF processor assignments

The advantage of using ICF Processors (PUs characterized as ICFs) instead of CPs for

Coupling Facility images is that because an ICF cannot run any z/OS or OS/390 operating

systems, software licenses are not charged for those processors.

The CFRM Policy utility now accepts two digit PARTITION

values.

Restriction: You must have compatibility or exploitation

function installed on all systems in the SYSPLEX to use

two digit partition values.

DATA TYPE(CFRM) REPORT(YES)

DEFINE POLICY NAME(POLICY1)

REPLACE(YES)

CF NAME(FACIL01)

TYPE(123456)

MFG(IBM)

PLANT(02)

SEQUENCE(123456789012)

PARTITION(01)

DUMPSPACE(2000)

CF NAME(FACIL02)

TYPE(123456)

MFG(IBM)

PLANT(02)

SEQUENCE(123456789012)

PARTITION(11)

DUMPSPACE(2000)

Meaning of PARTITION

Non z990: Partition number assigned when you defined

CF partition to HCD or IOCP

z990: LPAR identifier specified for CF partition in the

LPAR image profile

Applicable to both compatibility and exploitation systems

Note: There must be spare PUs to order dedicated ICFs. Refer to 2.2, “System design” on

page 38’ for details.

Chapter 7. Sysplex functions 167

CPs are Processor Units used to process z/OS, OS/390, CFCC, z/VM, Linux, TPF, VSE/ESA,

or z/VSE instructions. The logical partition can use dedicated

or shared CPs. However, it is

not possible to have a logical partition with dedicated

and shared CPs at the same time.

ICFs are PUs dedicated to process the CF Control Code (CFCC) on a Coupling Facility

image, which is always running on a logical partition. A CF image can use dedicated

and/or

shared ICFs. It can also use dedicated or shared CPs. With Dynamic ICF Expansion, a

Coupling Facility image can also use dedicated ICFs and shared CPs.

The z990 can have ICF processors defined to CF Images.

A z990 server Coupling Facility image can have one of the following defined in the image

profile:

򐂰 Dedicated ICFs

򐂰 Shared ICFs

򐂰 Dedicated

and shared ICFs

򐂰 Dedicated CPs

򐂰 Shared CPs

򐂰 Dedicated ICFs

and shared CPs

Shared ICFs add flexibility. However, running with shared Coupling Facility Processor Units

(ICFs or CPs) adds overhead to the coupling environment and is not a recommended

production configuration.

In Figure 7-4, the server on the left has two environments defined (Production and Test), each

having one z/OS and one Coupling Facility image. The Coupling Facility images are sharing

the same ICF processor. The logical partition Processing Weights are used to define how

much processor capacity each Coupling Facility image can have. The

Capped option can also

be set for the Test Coupling Facility Image, to protect the production environment.

Connections between these z/OS and Coupling Facility images can use IC channels to avoid

the use of real (external) coupling channels and to get the best link bandwidth available.

Figure 7-4 z990 ICF options - Shared ICFs

z/OS

Prod

z/OS

Prod

Function Setup

HMC

z990

Partition

Image

Profile

ICF

CP

CF

CF

Test Sy s pl e x

z/OS

Test

z/OS

Test

CF