Virtual machine storage policies capture storage characteristics that virtual machine home files and virtual disks require to run applications within the virtual machine. You can create several storage policies to define the types and classes of storage requirements.

Each storage policy is not only a set of constraints that apply simultaneously. A single policy can include alternative sets of subpolicies, or rule sets, that are datastore-specific and represent equally acceptable storage requirements. If you use vSphere APIs for I/O Filtering, the storage policy can include rules that are common for all storage types. The policy can contain only common rules, or only datastore-specific rule sets, or both.

When you create, clone, or migrate a virtual machine, you can apply the storage policy to the virtual machine. You can place the virtual machine in one of the datastores that matches the policy requirements. To match the policy requirement, the datastore must satisfy the following guidelines:
  • When I/O Filtering and common rules are not available, the datastore must satisfy all rules in at least one of the datastore specific rule sets.
  • With common rules enabled, the datastore must satisfy all common rules and all rules in at least one of the rule sets.

The virtual machine home files (.vmx, .vmsd, .nvram, .log, and so on) and the virtual disks (.vmdk) can have separate storage policies.

Table 1. Example Storage Policy for a Virtual Machine
Example Virtual Machine Files Example for a Storage Policy Example for a Datastore Compliant with the Storage Policy
windows_2008r2_test.vmx Storage Policy 2 datastore02, datastore05, datastore10
windows_2008r2_test.vmdk Storage Policy 3 datastore05
windows_2008r2_test_1.vmdk Storage Policy 5 datastore10