In this paper we will illustrate three basic steps for capacity planning:
1. Determine Service Level Requirements
The first step in the capacity planning process is to categorize the work done by systems and to quantify users’ expectations for how that work gets done.
2. Analyze Current Capacity
Next, the current capacity of the system must be analyzed to determine how it is meeting the needs of the users.
3. Planning for the future
Finally, using forecasts of future business activity, future system requirements are determined. Implementing the required changes in system configuration will ensure that sufficient capacity will be available to maintain service levels, even as circumstances change in the future.
Determine Service Level Requirements
We have organized this section as follows:
a. The overall process of establishing service level requirements first demands an understanding of workloads. We will explain how you can view system performance in business terms rather than technical ones, using workloads.
b. Next, we begin an example, showing workloads on a system running a back-end Oracle database.
c. Before setting service levels, you need to determine what unit you will use to measure the incoming work.
d. Finally, you establish service level requirements, the promised level that will be provided by the IT organization
There are several steps that should be performed during the analysis of capacity measurement data.
a. First, compare the measurements of any items referenced in service level agreements with their objectives. This provides the basic indication of whether the system has adequate capacity.
b. Next, check the usage of the various resources of the system (CPU, memory, and I/O devices). This analysis identifies highly used resources that may prove problematic now or in the future.
c. Look at the resource utilization for each workload. Ascertain which workloads are the major users of each resource. This helps narrow your attention to only the workloads that are making the greatest demands on system resources.
d. Determine where each workload is spending its time by analyzing the components of response time, allowing you to determine which system resources are responsible for the greatest portion of the response time for each workload.
Follow these steps:
a. First, you need to forecast what your organization will require of your IT systems in the future.
b. Once you know what to expect in terms of incoming work, you can use TeamQuest Model to determine the optimal system configuration for meeting service levels on into the future.
Capacity Planning Process
In summary, we have shown these basic steps toward developing a capacity plan:
1. Determine service level requirements
a. Define workloads
b. Determine the unit of work
c. Identify service levels for each workload
2. Analyze current system capacity
a. Measure service levels and compare to objectives
b. Measure overall resource usage
c. Measure resource usage by workload
d. Identify components of response time
3. Plan for the future
a. Determine future processing requirements
b. Plan future system configuration
By following these steps, you can help to ensure that your organization will be prepared for the future, ensuring that service level requirements will be met using an optimal configuration. You will have the information necessary to purchase only what you need, avoiding over-provisioning while at the same time assuring adequate service