The main responsibilities of the capacity manager are: • To develop and maintain the Capacity plan • Manage the process
capacity and performance. This should happen both when changes are proposed and after they are implemented. They pay particular attention to the cumulative effect of changes over a period of time. The cumulative effects of single changes can often cause degraded response times, file storage problems, and excess demand for processing capacity.
Other roles within Capacity Management are the roles of the network manager, application and system manger. They are responsible for translating the business requirements in to required capacity to be able to meet these requirements and to optimize the performance.
15.6 Relationships
Capacity Management is part of Service Delivery and is directly related to the business
requirements. It is not simply about the performance of the system’s components, individually or collectively.
Service Desk, Incident Management and Problem Management.
These processes will provide Capacity Management with information about incidents and problems related to Capacity. Capacity Management will support the processes with solving the incidents and or problems and also provide them with information about the capacity performance.
Change Management and Release Management
Capacity Management activities will raise Request for Changes (RFC's) in order to ensure that the appropriate capacity is available. These are subject to the Change Management process, and
implementation may affect several Configuration Items (C.I.'s), including hardware, software and documentation, and will require effective Release Management.
Availability Management
The link between Capacity Management and Availability Management is strong, as the availability that is needed requires a certain amount of capacity within the configuration items. Without enough capacity, you will never have enough availability. Furthermore, the values measured by Capacity Management are of importance to Availability Management in relation to availability and reliability.
Service Level Management
Both Capacity Management and Availability Management need to provide the service level manager with input for effective SLA negotiations. Capacity Management informs Service Level Management about the result levels that can be provided to the client.
Financial Management
The drafted capacity plan delivers important input for Financial Management, which on this basis can draft a very accurate investment plan capacity Management gets information in return about the available budget.
IT Service Continuity Management
Capacity Management provide ITSCM with the information about the minimum required Capacity needed for recovery. It is important to consider the impact (for needed capacity) of changes to the IT services on the ITSCM procedures.
Benefits
Implementation of Capacity Management offers the following benefits: • An actual overview of the current capacity in place
• The possibility to plan capacity in advance.
• Being able to estimate the impact of new applications or modifications • Cost savings
• Better service that is in tune with the requirements of the Business.
15.7 Common Problems
Common problems that can be encountered while the process is already implemented include: • Capacity information from suppliers is not available or is too general and can be misleading
for infrastructure components.
• The expectation to what Capacity Management can do is over estimated. If an application is poorly designed, more capacity won’t fix the problem.
• Information is difficult to obtain. It is not always easy to predict what future capacity is required before you build an application.
Note: This final point is important. All too often end users and customers are interviewed at length about their expected capacity requirements, only to demand more as soon as the new application goes live. It is up to the IT professionals to have built in the ability for the application to scale to match any new requirements.
Metrics
To verify if the process is operating within it goals one should check: • If the forecast is in line with the actual demand at that time? • If the Capacity plan is correct?
• Are the requirements being met?
• Is capacity not a cause for the breach of Service Levels, Incidents or Problems? • Are ad hoc expenses being reduced because better planning is in place? • Performance against SLAs
Best practices
Why a Capacity Plan?
With cheap hardware prices, capacity planning may seem unimportant; you can always upgrade later. A simple guess of the capacity requirements should be sufficient, right? Why give this subject any more thought?
There are two main issues that make capacity planning critical.
The first is the rate of technical change. We now measure progress in "Internet years" -- equivalent to about 90 days of a calendar year.
The second is with Internet/Intranet at the helm. Today’s systems are primarily being developed within a 3-tier architecture. This rapid change, coupled with the increase in complexity of 3-tier architecture, is causing system designers to pay closer attention to capacity. Five years ago, a designer could roll out a new system with a rough estimate of capacity and performance. The system could then be tuned or more capacity added before all of the users had been converted to the new system. The process was reasonable because the systems were typically not mission- critical.
Today, there’s no time for this approach. Once systems are in place they become an integral part of the overall design. Downing the system for upgrades becomes increasingly expensive in both time and resources. In addition, the added complexity of the environment typically requires more care, due to the interdependency between various application components.
Capacity planning is driven purely by financial considerations. Proper capacity planning can significantly reduce the overall cost of ownership of a system. Although formal capacity planning takes time, internal and external staff resources, software and hardware tools, the potential losses incurred without capacity planning are staggering. Lost productivity of end users in critical
business functions, overpaying for network equipment or services and the costs of upgrading systems already in production more than justify the cost of capacity planning.
Interesting websites: http://www.capacityplanning.com/ Assessment http://www.itil.co.uk/online_ordering/serv_del_graphs/capacity_mngt.htm White Papers
http://www.interpromusa.com/ASPs and Application Performance Mgmt.pdf http://www.iccmforum.com/iccm.asp?r=Capacity&s=CPUResource
Tools
http://regions.cmg.org/regions/cmgarmw/shortarm.html
http://www.iccmforum.com/iccm.asp?r=Tutorial&s=Benchmarks&t=Standard http://www.iccmforum.com/iccm.asp?r=Tutorial&s=Benchmarks&t=ZiffDavis