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Chapter 3 E-business infrastructure 173

Mini Case Study 3.5 Virtualization cuts costs and improves service

The Association of Teachers and Lecturers (ATL) is using virtualization to not only cut hardware costs, but
also to recover quickly from systems failures and maintain business continuity. The Association of Teachers
and Lecturers is an independent, registered trade union and professional association representing approxi-
mately 160,000 teachers, lecturers and support staff in maintained and independent nurseries, schools, sixth
forms, and tertiary and further education colleges in the UK.
Ann Raimondo, head of information technology at ATL, is responsible for managing the IT infrastructure
for the ever-expanding organization, including deploying equipment, IT support and training for its 150
employees. In addition to offices in London, Belfast and Cardiff, the ATL has a large volunteer base of remote
workers throughout the UK who require IT systems and support. In her role, Raimondo was faced with the
following challenges:
Fifty per cent of the available server storage space was not utilized
Seventy-two per cent of the storage space purchased was not being used
Storage space could not be reallocated to other systems in need of additional storage
Data were physically bound to a server, so if corruption occurred to the operating system or applications,
the data on physical drives could not be reattached easily to another server and would need to be restored
from backup.
The implementation resulted in the following benefits:
Server consolidation. ATL consolidated from 22 servers to 11, reducing hardware requirements and
costs by 50 per cent.
Flexibility and responsiveness. Prior to bringing in ESX Server, deploying a new server would require
approximately three weeks for sourcing, ordering and implementing hardware. With VMware virtual infra-
structure, this same process takes less than one hour.
Lowered the cost of disaster recovery. The hardware independence of VMware virtual infrastructure
helps mitigate failures caused by hardware and enables recovery from a disaster in a matter of minutes,
matching and improving on user downtime expectations.
Source: VMware (2007)

Service-oriented architecture (SOA)

Service-oriented The technical architecture used to build web services is formally known as a ‘service-
architecture oriented architecture’. This is an arrangement of software processes or agents which
A service-oriented
architecture is a collection communicate with each other to deliver the business requirements.
of services that The main role of a service within SOA is to provide functionality. This is provided by
communicate with each three characteristics:
other as part of a
distributed systems
architecture comprising 1 An interface with the service which is platform-independent (not dependent on a partic-
different services. ular type of software or hardware). The interface is accessible through applications devel-
opment approaches such as Microsoft .Net or Java and accessed through protocols such as
SOAP (Simple Object Access Protocol) which is used for XML-formatted messages, i.e.
instructions and returned results to be exchanged between services.
2 The service can be dynamically located and invoked. One service can query for the exis-
tence of another service through a service directory – for example an e-commerce service
could query for the existence of a credit card authorization service.
3 The service is self-contained. That is, the service cannot be influenced by other services;
rather it will return a required result to a request from another service, but will not change
state. Within web services, messages and data are typically exchanged between services
using XML.