IBM eServer zSeries 900 Technical Guide

12 IBM eServer zSeries 900 Technical Guide

Intelligent Resource Director uses the concept of an LPAR cluster, the subset of z/OS

systems in a Parallel Sysplex cluster that are running as LPARs on the same z900 server. In a

Parallel Sysplex environment, Workload Manager directs work to the appropriate resources

based on business policy. With IRD, resources are directed to the priority work. Together,

Parallel Sysplex technology and IRD provide the flexibility and responsiveness to e-business

workloads unrivaled in the industry.

IRD has three functions: LPAR CPU management, dynamic channel path management, and

channel subsystem priority queuing.

LPAR CPU management

Workload Manager (WLM) and PR/SM dynamically adjust the weight and the number of

logical processors within a logical partition and the processor weight based on the WLM

policy. The ability to move the CPU weights across an LPAR cluster provides processing

power to where it is most needed based on WLM goal mode policy.

The z/OS V1 R2 WLM also implements the capability for LPAR weight management of CPs

for non-z/OS logical partitions, running Linux or z/VM operating systems.

Dynamic channel path management

This feature enables customers to have channel paths that dynamically and automatically

move to those I/O devices that have a need for additional bandwidth due to high I/O activity.

The benefits are enhanced by the use of goal mode and clustered LPARs.

Channel subsystem priority queuing

Channel subsystem priority queuing on the z900 allows priority queueing of I/O requests

within the channel subsystem and the specification of relative priority among LPARs. WLM in

goal mode sets priorities for an LPAR and coordinates this activity among clustered LPARs.

1.3.7 Workload License Charge

Workload License Charge (WLC) is a software license charge option available on z900 for the

z/OS operating system and some related products. WLC allows sub-capacity software

charges, which are based on z/OS logical partition utilization rather than in the server’s total

Million Service Units (MSUs) value. The logical partition utilization is based on the rolling

4-hour average utilization value.

WLC sub-capacity implements the software charges independency from the hardware

installed capacity, allowing independent growth of hardware and software. With sub-capacity,

a z900 model upgrade changing the server’s MSUs does

not affect software charges for

Variable WLC (VWLC) products; software charges on these products are affected by the

logical partition utilization where they run.

1.3.8 Hardware consoles

Hardware Management Console and Support Element interface

On z900 servers the Hardware Management Console (HMC) provides the platform and user

interface that can control and monitor the status of the system via the two redundant Support

Elements installed in each z900.

The z900 server implements two fully redundant interfaces, known as the Power Service

Control Network (PSCN), between the two Support Elements and the CPC.

Error detection and automatic switch-over between the two redundant Support Elements

provides enhanced reliability and availability.