z/OS Introduction and Workshop
Sysplex, Parallel Sysplex
&
Geographically Dispersed Parallel Sysplex
© 2017 IBM Corporation
Unit Objectives
After completing this unit, you should be able to:
•Describe difference between Sysplex, Parallel Sysplex, and GDPS
•Describe Coupling Facility
•Describe Sysplex Timer
•List types of GDPS configurations
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System z Clustering Terminology
A sysplex is a collection of z/OS systems that cooperate, using certain
hardware and software products, to process work. It is a clustering
technology that can provide near-continuous availability.
A Parallel Sysplex is a sysplex that uses multisystem data-sharing
technology. It allows direct, concurrent read/write access to shared data
from all processing nodes (or servers) in the configuration without
impacting performance or data integrity. As many as 32 servers can
concurrently cache shared data in local processor memory through
hardware-assisted cluster-wide serialization and coherency controls. As a
result, work requests that are associated with a single workload, such as
business transactions or database queries, can be dynamically distributed
for parallel execution on nodes in the sysplex cluster based on available
processor capacity.
In many ways a Parallel Sysplex system appears as a single large system.
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Parallel Sysplex Benefits
The primary goal of a Parallel Sysplex is to provide data sharing capabilities,
allowing multiple databases for direct reads and writes to shared data. Benefits
include:
Help remove single points of failure within the server, LPAR, or subsystems
Application Availability
Single System Image
Dynamic Session Balancing
Dynamic Transaction Routing
Scalable capacity
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CF (Coupling Facility)
LPAR microcode serving as shared
memory for all participating z/OS
environments
Sysplex Timer
Synchronize clocks of all member systems
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LPAR
Logical Partition enable
sharing of processors and
channels (not memory)
Coupling Facility
Has memory accessible to
all participating members
using CF channels for
communication between
participating members
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GDPS – Highest Availability
Geographically Dispersed Parallel Sysplex (GDPS) is an extension of
Parallel Sysplex of mainframes located, potentially, in different cities.
GDPS includes configurations for single site or multiple site configurations:
HyperSwap Manager (peer-to-peer copy, same data center)
PPRC (peer-to-peer copy, up to 120 miles data center separation)
XRC (extended remote copy, no distance restrictions, recovery process
must be initiated)
GM (global mirroring, designed to recover from total failure)
MGM (more than two sites)
Active-Active (continuous availability, multiple sites, load balancing)
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GDPS
Processing memory and disk storage
updates are maintained protecting
against failures
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Parallel Sysplex Documentation & Information
IBM Redbooks
z/OS Parallel Sysplex Configuration Overview (SG24-6485-00)
IBM Manuals
Setting Up a Sysplex (SA22-7625-18)
Sysplex Services Guide (SA22-7617-13)
Sysplex Services References (SA22-7618-12)
9 © 2017 IBM Corporation
Unit summary
Having completed this unit, you should be able to:
Describe difference between sysplex, Parallel Sysplex, and GDPS
Describe Coupling Facility
Describe Sysplex Timer
List types of GDPS configurations
10 © 2017 IBM Corporation
