Availability Management

Capacity Planning

During Service Design and Service Transition, the capacity requirement s of IT service s are calculated. A forward-looking capacity plan should be maintained and regularly updated and Service Operation will have a role to play in this. Such a plan should look forward up to two years or more, but should be review ed regularly every three to 12 months, depending upon volatility and resources available.

The plan should be linked to the organization ’s financial planning cycle, so that any required expenditure for infrastructure upgrades, enhancements or additions can be included in budget estimates and approved in advance.

The plan should predict the future but must also examine and report upon previous predictions, particularly to give some confidence in further predictions. Where any discrepancies have been encountered, these should be explained and future remedial action described.

The Capacity Plan might typically cover:

• Current performance and utilization details, with recent trends for all key CIs, including
• Backbone networks
• LANs
• Mainframes (if still used)
• Key server s
• Main data storage devices
• Selected (representative) desktop and laptop equipment
• Key websites
• Key databases
• Key application s
• Operational capacity – electricity, floor space, environmental capacity (air condition), floor weighting, heat generation and output, electrical and water demand and supply etc.
• Magnetic media.
• Estimated performance and utilization for all such CIs during the planning period (e.g. the next three months)
• Comparative data with previous estimates – to allow confidence in future estimates to be judged
• Reports on any specific capacity difficulties encountered in the past period, with details of recovery and preventive actions taken for the future
• Details of any required upgrades or procurements needed and planned for the future, with indicative cost s and timescales.
• Any potential capacity risks that are likely – with suggested countermeasure s should they arise.

During Service Design and Service Transition, IT service s are designed for availability and recovery. Service Operation is responsible for actually making the IT service available to the specified user s at the required time and at the agreed levels.

During Service Operation the IT teams and users are in the best position to detect whether services actually meet the agreed requirement s and whether the design of these services is effective.

What seems like a good idea during the Design phase may not actually be practical or optimal. The experience of the users and operational function s makes them a primary input into the ongoing improvement of existing services and the design.

However, there are a number of challenges with gaining access to this knowledge:

• Most of the experiences of the operational teams and users are either informal, or spread across multiple sources.
• The process for collecting and collating this data needs to be formalized.
• Users and operational staff are usually fully occupied with their regular activities and tasks and it is very difficult for them to be involved in regular planning and design activities. One argument often made here is that if design is improved, the operational teams will be less busy resolving problem s and will therefore have more time to be involved in design activities. However, practice shows that as soon as staff are freed up, they often become the target of workforce reduction exercises.

Having said this, there are three key opportunities for operational staff to be involved in Availability Improvement, since these are generally viewed as part of their ongoing responsibility:

• Review of maintenance activities. Service Design will define detailed maintenance schedules and activities, which are required to keep IT services functioning at the required level of performance and availability. Regular comparison of actual maintenance activities and times with the plan s will highlight potential areas for improvement. One of the sources of this information is a review of whether Service Maintenance Objective s were met and, if not, why not.
• Major problem reviews. Problems could be the result of any number of factors, one of which is poor design. Problem reviews therefore may include opportunities to identify improvements to the design of IT services, which will include availability and capacity improvement.
• Involvement in specific initiatives using techniques such as Service Failure Analysis (SFA), Component Failure Impact Analysis (CFIA), or Fault Tree Analysis (FTA) or as members of Technical Observation (TO) activities – either as part of the follow-up to major problem s or as part of an ongoing service improvement programme, in collaboration with dedicated Availability Management staff. These Availability Management techniques are explained in more detail in the Service Design publication.

There may be occasions when Operational Staff themselves need downtime of one or more services to enable them to conduct their operational or maintenance activities – which may impact on availability if not properly scheduled and managed. In such cases they must liaise with SLM and Availability Management staff – who will negotiate with the business/users, often using the Service Desk to perform this role, to agree and schedule such activities.

Дата добавления: 2014-12-23