Appendix C: Capacity Planning
   
Appendix C: Capacity Planning
Capacity forecasting provides an efficient way to acquire the appropriate amount of physical resources to support the increased demand for the vCloud. This allows for the growth of vCloud to be planned and included in the service providers’ budgetary process, and reduces the likelihood of “panic buying,” which generally increases costs dramatically and undermines standardization efforts. Capacity planning also reduces the likelihood of last minute surprises, such as a lack of available space or power to support the new vCloud infrastructure components.
From a vCloud perspective, capacity management is simplified by the existence of the provider virtual datacenter and organization virtual datacenter constructs, but potentially more complicated by the addition of three models of consumption: Pay As You Go, Allocation Pool (committed), and Reservation Pool (dedicated). Finally, all of these capacity management aspects must address both the vCloud (service provider) administrator and the customer (organization) administrator perspectives.
Sizing for workload resource group clusters can be difficult to predict because the provider is not in charge of what the consumer may run. The provider is also not aware of existing usage statistics for virtual machines that are run in the vCloud. The following information should assist in initial sizing of the vCloud environment and is based on information from Service Definitions. This information is provided in the form of examples. A local VMware representative can assist with detailed sizing of the environment.