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The Capacity Plan should be published annually in line with the budgetary cycle. Ideally it should be updated quarterly. This takes extra effort, but, if it is regularly updated, the Capacity Plan is more likely to be accurate and to reflect the changing business need.
Capacity Management is also responsible for advising the SLM process about
appropriate service levels or service level options.
This Section briefly explains the background to this issue of the Capacity
Plan. For example:
The introduction should also include the following Sub-sections:
Ideally, the Capacity Plan should encompass all IT resources. This Sub-section should explicitly name those elements of the IT Infrastructure that are included.
The Capacity Plan uses information gathered by the sub-processes. This Sub-section therefore should contain details of how and when this information was obtained, for example business forecasts obtained from business plans, workload forecasts obtained from Customers, service level forecasts obtained by the use of modelling tools.
It is important that any assumptions made, particularly those concerning the business drivers for IT Capacity, are highlighted early on in the plan. If they are the cornerstones upon which more detailed calculations are built, then it is vital that all concerned understand this.
Much of the Capacity Plan, by necessity, contains technical detail that is not be of interest to all readers of the plan. The management summary should highlight the main issues, options, recommendations and costs. It may be necessary to produce a separate executive summary document that contains the main points from each of the sections of the main plan.
It is necessary to put the plan into the context of the current and envisaged business environment. For example, a British airline planned to move a large number of staff into its headquarters building. A ratio of 1.7 people per desktop terminal was forecast. Capacity Management was alerted and was able to calculate the extra network traffic that would result.
It is important to explicitly mention all known business forecasts so that readers can determine what is in and what is outside the scope of the plan.
The service summary section should include the following:
For each service that is delivered, provide a service profile. This should include throughput rates and the resulting resource utilisation, for example of memory, storage space, transfer rates, processor usage, network usage. Short term, medium term and long-term trends should be presented here.
The business plans should provide Capacity Management with details of the new services planned, and the growth or contraction in the use of existing services. This Sub-section should report on new services and the demise of legacy systems.
The resource summary section should include the following:
This Sub-section concentrates on the resulting resource usage by the services. It reports, again, on the short, medium and long-term trends in resource usage, broken down by hardware platform. This information has been gathered and analysed by the sub-processes of Service Capacity Management and Resource Capacity Management and so should be readily available.
This Sub-section forecasts the likely resource usage resulting from the service forecasts. Each business scenario mentioned above should be addressed here. For example, a carpet wholesale business in the North of England could accurately predict what the peak and average processor usage would be before they decided to take over a rival business. It was proved that an upgrade would not be required. This was fed into the cost model, leading to a successful take-over.
Building on the results of the previous Section, this Section outlines the possible options for improving the effectiveness and efficiency of Service Delivery. It could contain options for merging different services on a single processor, upgrading the network to take advantage of technological advances, tuning the use of resource or service performance, rewriting legacy systems, purchasing new hardware or software etc.
The costs associated with these options should be documented here. In addition the current and forecast cost of providing IT Services should be included. In practice Capacity Management obtains much of this information from the Financial Management process and the IT Financial Plan.
The final section of the plan should contain a summary of the recommendations made in the previous plan and their status, for example rejected, planned, implemented. Any new recommendations should be made here, i.e. which of the options mentioned in the plan is preferred.
The recommendations should be quantified in terms of:
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