IBM eServer zSeries 900 Technical Guide

Chapter 2. zSeries 900 system structure 31

򐂰 Processor(s)

Called

Logical Processor(s), they can de defined as CPs, IFLs or ICFs. They can be

dedicated to a partition or shared between all partitions. When shared, a processor weight

can be defined to provide the required level of processor resources to a logical partition.

Also, the

capping option can be turned on, which prevents a logical partition from

acquiring more than its defined weight, limiting its processor consumption.

For z/OS Workload License Charge (WLC), a logical partition “Defined Capacity” can be

set, enabling the

soft capping function. See 7.9, “Workload License Charges” on page 239

for details.

Only Coupling Facility (CF) partitions can have both dedicated

and shared logical

processors defined.

The number of defined logical processors can be up to the number of “real” processors

available. However, additional

reserved processors can be defined to allow nondisruptive

processor upgrades to a logical partition. The weight and the number of online logical

processors of a logical partition can be dynamically managed by the LPAR CPU

Management function of the Intelligent Resource Director, to achieve the defined goals of

this specific partition and of the overall system.

򐂰 Memory

Memory, either Central Storage or Expanded Storage, must be dedicated to a logical

partition. The defined storage(s) must be available during the logical partition activation,

otherwise the activation fails.

Reserved storage can be defined to a logical partition, enabling concurrent memory add to

and removal from a logical partition, using the LPAR Dynamic Storage Reconfiguration.

See “LPAR Dynamic Storage Reconfiguration” on page 56.

򐂰 Channels

Channels (other than parallel channels) can be shared between logical partitions, by

including the partition name in the partition list of a Channel Path ID (CHPID). I/O

configurations are done by the I/O Configuration Program (IOCP) or the Hardware

Configuration Dialog (HCD). IOCP is available on z/OS, OS/390, z/VM, VM/ESA, and

VSE/ESA operating systems, and in the z900 hardware console. HCD is available on z/OS

and OS/390 operating systems.

ESCON and FICON channels can be

managed by the Dynamic CHPID Management

(DCM) function of the Intelligent Resource Director. DCM enables the system to respond

to ever changing channel requirements by moving channels from lesser used control units

to more heavily used control units as needed.

2.3.1 Basic Mode

In Basic Mode a z900 server can use only CPs and SAPs, because IFL and ICF processors

can only be defined and used in LPAR Mode. In Basic Mode a z900 server can be defined to

operate in one of the following image modes:

򐂰 ESA/390 Mode, to run:

– An z/Architecture operating system image, only on CPs.

– An ESA/390 operating system image, only on CPs.

– A Linux operating system image, only on CPs.

򐂰 ESA/390 TPF Mode, to run:

– A TPF operating system image, only on CPs.

Table 2-1 shows the required PU types and operating systems for Basic Modes.