| Systems that work well during
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| |
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| development, deployed on a small scale,
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| | 1. Research and quantify the data volumes
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| can fail to meet performance goals when
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| | and transaction volumes the target market
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| the deployment is scaled up to support
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| | implies. Some of these figures can be eye
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| real levels of use.
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| | openers and help the business users
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| An apposite example of this comes from a
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| | realise the full scale of the system.
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| major blue chip company that recently
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| | This alone can lead to reassessment of
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| outsourced the development of an
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| | the priority of many features.
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| innovative high technology platform.
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| | 2. Determine the way features could be
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| Though development was behind schedule
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| | presented to users and the system
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| this was deemed acceptable. The system
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| | structured in order to make scaling of
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| gradually passed through functional
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| | the system easier. Do not try and have
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| elements of the user acceptance testing
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| | the same functionality you would have for
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| and eventually it looked like a
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| | a single user desktop solution provide an
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| deployment date could be set. But then
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| | appropriate scalable alternative.
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| the supplier started load testing and
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| | 3. Recognise that an intrinsic part of
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| scalability testing. There followed a
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| | the development process is load testing
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| prolonged and costly period of
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| | at representative scale on each
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| architectural changes and changes to the
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| | incremental software release. This is
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| system requirements. The supplier battled
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| | continual testing, focusing on the
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| heroically to provide an acceptable
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| | biggest risk to the project: the ability
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| system, until finally the project was
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| | to operate at full scale.
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| mothballed.
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| | 4. Ensure load testing is adequate both
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| This is not an isolated case. IT folklore
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| | in scope and rigour. Load testing is not
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| abounds with similar tales. From
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| | just about measuring response times with
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| ambulance dispatch systems to web-sites
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| | a performance test. The load testing
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| for the electronic submission of tax
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| | programme needs to include other types of
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| returns, systems fail as they scale and
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| | load testing including stress testing,
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| experience peak demands. All of these
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| | reliability testing, and endurance
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| projects appear not to have identified
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| | testing.
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| and ordered the major risks they faced.
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| | 5. Don?t forget that failures will occur.
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| This is a fundamental stage of risk based
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| | Large scale systems generally include
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| testing, and applies equally to
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| | server clusters with fail-over behaviour.
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| scalability testing or load testing as it
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| | Failure testing, fail-over testing and
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| does to functionality testing or business
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| | recovery testing carried out on
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| continuity testing. With no risk
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| | representative scale systems operating
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| assessment they did not recognise that
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| | under load should be included.
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| scaling was amongst the biggest risks,
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| | 6. Don?t forget catastrophic failure
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| far more so that delivering all the
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| | could occur. For large scale problems,
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| functionality
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| | disaster testing and disaster recovery
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| Recent trends towards Service Oriented
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| | testing should be carried out at
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| Architecture (SOA) attempt to address the
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| | representative scale and loads. These
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| issue of scalability but also introduce
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| | activities can be considered the
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| new issues. Incorporating externally
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| | technical layers of business continuity
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| provided services into your overall
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| | testing.
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| solution means that your ability to scale
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| | 7. Recognise external services if you use
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| now depends upon these external system
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| | them. Where you are adopting an SOA
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| operate under load. Assuring this is a
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| | approach and are dependent on external
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| demanding task and sadly the load testing
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| | services you need to be certain that the
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| and stress testing here is often
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| | throughput and turnaround time on these
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| overlooked.
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| | services will remain acceptable as your
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| Better practice is to start the
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| | system scales and its demands increase. A
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| development of a large scale software
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| | smart system architecture will include a
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| system with its performance clearly in
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| | graceful response and fall-back operation
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| mind, particularly scalability testing,
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| | should the external service behaviour
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| volume testing and load testing. To
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| | deteriorate or fail.
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| create this performance testing focus:
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|
