IBM 990 - Manual (Page 170)

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zSeries 990 Technical Guide
Systems management
The Parallel Sysplex architecture provides the infrastructure to satisfy a customer
requirement for continuous availability, while providing techniques for achieving simplified
systems management consistent with this requirement. Some of the features of the Parallel
Sysplex solution that contribute to increased availability also help to eliminate some systems
management tasks. Examples include:
z/OS or OS/390 Workload Manager
The Workload Manager (WLM) component of z/OS or OS/390 provides sysplex-wide
workload management capabilities based on installation-specified performance goals and
the business importance of the workloads. The Workload Manager tries to attain the
performance goals through dynamic resource distribution. WLM provides the Parallel
Sysplex cluster with the intelligence to determine where work needs to be processed and
in what priority. The priority is based on the customer's business goals and is managed by
sysplex technology.
Sysplex Failure Manager
The Sysplex Failure Management component of z/OS or OS/390 allows the installation to
specify failure detection intervals and recovery actions to be initiated in the event of the
failure of an image in the sysplex.
Automatic Restart Manager
The Automatic Restart Manager (ARM), a component of z/OS or OS/390, enables fast
recovery of the subsystems that might hold critical resources at the time of failure. If other
instances of the subsystem in the Parallel Sysplex need any of these critical resources,
fast recovery will make these resources available more quickly. Even though automation
packages are used today to restart the subsystem to resolve such deadlocks, ARM can be
activated closer to the time of failure.
Cloning/symbolics
Cloning refers to replicating the hardware and software configurations across the different
physical servers in the Parallel Sysplex, that is, an application that is going to take
advantage of parallel processing might have identical instances running on all images in
the Parallel Sysplex. The hardware and software supporting these applications could also
be configured identically on all images in the Parallel Sysplex to reduce the amount of
work required to define and support the environment.
Resource sharing
A number of base z/OS or OS/390 components exploit Coupling Facility shared storage,
providing an excellent medium for sharing component information for the purpose of
multi-image resource management. This exploitation, called IBM
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zSeries Resource
Sharing, enables sharing of physical resources such as files, tape drives, consoles, catalogs,
and so forth, with significant improvements in cost, performance, and simplified systems
management. The zSeries Resource Sharing delivers immediate value, even for customers
who are not leveraging data sharing, through exploitation delivered with the base z/OS or
OS/390 software stack.
Single system image
Even though there could be multiple servers and z/OS or OS/390 images in the Parallel
Sysplex cluster, it is essential that the collection of images in the Parallel Sysplex appear as a
single entity to the operator, the end user, the database administrator, and so on. A single
system image ensures reduced complexity from both operational and definition perspectives.
Regardless of the number of images and the underlying hardware, the Parallel Sysplex
cluster appears as a single system image from several perspectives: