Service Design
Availability Management
Introduction
The Availability
Management
process ensures
that IT services
consistently
deliver the required level of availability.
Purpose
Availability Management is a process
that ensures the availability
of systems and services matches evolving agreed
needs of the business.
Availability
Management
also ensures IT delivers the right levels of service availability.
The purpose of Availability Management is to
optimize the capability of the IT infrastructure and to support
the organization
by
delivering a
cost-effective and sustained level of availability that enables the business to satisfy its objectives.
Objectives
The objectives of Availability Management are to:
• Produce and maintain an appropriate and updated Availability Plan.
• Provide advice and guidance to all other areas of the business.
• Ensure service
availability achievements meet or exceed agreed targets.
• Assist with diagnosis
and
resolution of availability-related
incidents
and problems.
• Assess the impact of all changes
within the Availability Plan.
• Ensure proactive measures
are taken
to improve the availability of services
implemented.
Overview
Activities performed by Availability Management involves planning availability before, during and after a service is provided.
The two key elements of Availability Management are:
• Reactive activities: Involves the monitoring,
measuring analysis and management of all events, incidents and problem-solving unavailability.
• Proactive activities: Involve the proactive planning, design and improvement of availability.
The two inter-connected
levels to complete Availability Management are:
• Service availability: Involves all aspects and impacts of service availability and unavailability.
• Component availability: Involves
all aspects of component
availability
and unavailability.
Component Availability is
aiming at the proper functioning of a
single component (e.g. system or hardware)
where Service Availability is aiming at the proper
functioning of a service end-to-end including all the needed components.
Concepts
The following are important concepts of Availability Management:
• Availability: The ability of a service, component or CI to perform
its agreed function when required.
• Reliability: A measure
of how long a service, component or CI can perform its agreed function without
interruption.
• Maintainability: A measure of how quickly and effectively a service, component or CI can be restored to normal working after a failure.
• Resilience (Redundancy): The ability of a component or service
to keep running where one or more components failed.
• Serviceability: The
ability of a third party supplier to meet the terms
of their contract.
• Security: information Security Management determines the security requirements of a service, while Availability Management implements the measures.
• Vital Business
Function
(VBF): VBF reflects the business critical elements
of the business process supported by an IT service.
Vital Business Function
The term vital business function (VBF)
is used to reflect
the
part
of a business process that is critical to the success of the business.
An IT service may support a number of business functions that are less critical.
For example, an automated teller machine (ATM)
or cash dispenser service, VBF would be the dispensing of cash. However, the ability
to obtain a statement from an ATM may
not
be
considered
as vital. This
distinction
is important and should influence availability design and associated costs.
The more vital the business function generally, the greater the level of resilience and availability that needs to
be incorporated into the design required in
the supporting IT services.
For all services,
whether VBFs
or not, the availability
requirements should
be determined by the business
and not by IT.
Certain VBFs may need special designs, which are now being used as a matter of course
within service design plans, incorporating:
High availability: A characteristic of the IT service that minimizes or masks the effects
of IT component failure to the users of a service.
Fault tolerance: The ability of an IT service, component or CI to continue to operate correctly after failure of a component part.
Continuous operation:
An approach or
design to eliminate planned downtime of an IT service.
Note that individual components or CIs may be down even though the IT service remains
available.
Continuous
availability: An approach
or
design
to
achieve 100% availability.
A
continuously available IT service has no planned or unplanned downtime
Role
The responsibilities of an Availability Manager
include:
• Ensure all existing
services deliver
the
levels
of
availability
that
has been
agreed.
• Ensure all
new
services
are
designed
to
deliver
the
levels
of
availability
required.
• Assist with investigation and diagnosis of all incidents
and problems caused by unavailability of services or components.
• Participate in the IT infrastructure design.
• Monitor and report actual IT availability achieved against SLA targets.
• Proactively improve service availability.
• Create, maintain and regularly review AMIS.
• Ensure techniques
and methods
associated to the Availability
Management process are regularly reviewed and audited.
• Ensure the levels of IT availability required are cost-justified.
• Assess management of risk.
• Assess changes for impact.
• Attend CAB meetings.
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