Choosing the Storage API to Use

The
HostStorageSystem
APIs are low-level enough for performing VMFS provisioning operations. They require a knowledge of partitioning details and VMFS extent composition. They do not enforce VMFS best practices like partition alignment and optimum VMFS block sizes, and they allow you to mix extents from different datastores on the same LUN and to add extents even though expansion is preferable in most cases.
The
HostDatastoreSystem
APIs are primarily used for managing VMFS volumes. They don’t require an in-depth knowledge of storage systems, and do enforce best practices.
Figure 1 gives an overview of the different APIs. See Managed Objects for Working with Storage to determine which tasks are commonly performed with which API.
Storage APIs