The storage class definition in vSphere maps to policies that are defined through vSAN SPBM to achieve different levels of service level agreements (SLAs) and quality of service (QoS), and can leverage these benefits from advanced vSAN data service functionalities such as de-duplication, compression, and checksums. Using general policies is advisable if no specific use cases exist.
Start by assessing the following different application requirements:
- I/O performance and the profile of your workloads on a per-virtual-disk basis
- Working sets of your workloads
- Hot-add (feature of vSphere) of additional cache requires re-population of the cache
- Specific application best practices, such as block size
