You can create storage reservation policies to allow blueprint architects to assign the volumes of a virtual machine to different datastores for the vSphere, KVM (RHEV), and SCVMM platform types or different storage profiles for other resources, such as vCloud Air or vCloud Director resources.
Assigning the volumes of a virtual machine to different datastores or to a different storage profile allows blueprint architects to control and use storage space more effectively. For example, they might deploy the operating system volume to a slower, less expensive datastore, or storage profile, and the database volume to a faster datastore or storage profile.
Some machine endpoints only support a single storage profile, while others support multi-level disk storage. Multi-level disk storage is available for vCloud Director 5.6 and greater endpoints and for vCloud Air endpoints. Multi-level disk storage is not supported for vCloud Director 5.5 endpoints.
When you create a blueprint, you can assign a single datastore or a storage reservation policy that represents multiple datastores to a volume. When they assign a single datastore, or storage profile, to a volume, vRealize Automation uses that datastore or storage profile at provisioning time, if possible. When they assign a storage reservation policy to a volume, vRealize Automation uses one of its datastores, or storage profiles if working with other resources, such as vCloud Air or vCloud Director, at provisioning time.
A storage reservation policy is essentially a tag applied to one or more datastores or storage profiles by a fabric administrator to group datastores or storage profiles that have similar characteristics, such as speed or price. A datastore or storage profile can be assigned to only one storage reservation policy at a time, but a storage reservation policy can have many different datastores or storage profiles.
You can create a storage reservation policy and assign it to one or more datastores or storage profiles. A blueprint creator can then assign the storage reservation policy to a volume in a virtual blueprint. When a user requests a machine that uses the blueprint, vRealize Automation uses the storage reservation policy specified in the blueprint to select a datastore or storage profile for the machine’s volume.
If you have SDRS enabled on your platform, you can allow SDRS to load balance storage for individual virtual machine disks, or all storage for the virtual machine. If you are working with SDRS datastore clusters, conflicts can occur when you use reservation policies and storage reservation policies. For example, if a standalone datastore or a datastore within an SDRS cluster is selected on one of the reservations in a policy or storage policy, your virtual machine storage might be frozen instead of driven by SDRS. If you request reprovisioning for a machine with storage placement on an SDRS cluster, the machine is deleted if the SDRS automation level is disabled.