8.2 Capacity Management
Capacity Management focuses on providing vCloud capacity to meet both existing and future needs in support of vCloud service offerings.
For the vCloud provider, the goal of capacity planning is to provide sufficient capacity within the vCloud infrastructure to meet the current and future needs of the services offered to customers. Sufficient reserve capacity must be maintained in the vCloud Infrastructure to prevent virtual machines and vApps from contending for resources under normal circumstances, thus breaching agreed services levels.
The vCloud provider components needs to manage the following:
The management cluster that contains all the components used to create and manage the vCloud.
The resource clusters that provide resources to the vCloud consumers. The sizing of the management cluster is generally predictable, but consideration needs to be given for the number of vCloud Director cells and the size of the vCloud Director, vCenter, and Chargeback databases. Additionally, if vCenter Operations is used, the storage required for vApps needs to be considered because it can be substantial in large environments. Initial sizing guidelines for the management cluster are provided in Architecting a VMware vCloud.
The vCloud consumer resources (such as vApps and organization virtual datacenters) could have unpredictable usage. To size consumer resources, estimate the initial capacity required and use vCloud Capacity Management techniques, which predict future usage needs based upon past usage trends.
Capacity planning is required to make sure that the vCloud resources supplied to the tenant are used appropriately, are available when required, and expand or contract depending on current and future demand.