A vRealize Automation reservation can define policies, priorities, and quotas that determine machine placement for provisioning requests.
Reservation policies restrict machine provisioning to a subset of available reservations. Storage reservation policies allow blueprint architects to assign machine volumes to different datastores.
- How much storage is available on the data store/cluster.
- How much of that storage is reserved for that data store/cluster.
- How much of that storage is already allocated in vRealize Automation
For example, even if the vCenter Server has storage available for the data store/cluster, if sufficient storage is not reserved in the reservation then provisioning fails with a "No reservation is available to allocate..." error. The allocated storage on a reservation depends on the number of VMs (regardless of their state) on that specific reservation. See the VMware Knowledge Base article Machine XXX: No reservation is available to allocate within the group XXX. Total XX GB of storage was requested (2151030) at http://kb.vmware.com/kb/2151030 for more information.