Appendix C: Capacity Planning : vCloud Administrator (Service Provider) Perspective : Storage
VMware vCloud Director uses a largest available capacity algorithm for deploying virtual machines to datastores. Storage capacity must be managed on both an individual datastore basis as well as in the aggregate for a provider virtual datacenter.
In addition to considering VMware storage allocation design guidelines, manage capacity at the datastore level using the largest virtual machine storage configuration, in terms of units of consumption, offered in the service catalog when determining the amount of spare capacity to reserve. For example, if using 1TB datastores (100 storage units of consumption based on a 10GB unit of consumption) and the largest virtual machine storage configuration is six storage units of consumption (60GB), then applying the VMware design guideline of approximately 80% datastore utilization implies managing to 82 storage units of consumption. This would result in 82% datastore utilization and reserve capacity equivalent to three of the largest virtual machines offered in the service catalog in terms of storage.