Storage Policy Based Management (SPBM): VMware Cloud Director uses SPBM to define storage characteristics. Within a software-defined data center, SPBM plays a major role by helping to align storage with application demands of your virtual machines. It provides a storage policy framework that serves as a single unified control panel across a broad range of data services and storage solutions.
As an abstraction layer, SPBM abstracts storage services delivered by vVols, vSAN, I/O filters, or other storage entities. Instead of integrating with each individual type of storage and data services, SPBM provides a universal framework for different types of storage entities.
SPBM provides the following mechanisms:
Advertisement of storage capabilities and data services that storage arrays and other entities such as I/O filters offer.
Bidirectional communications between ESXi and vCenter Server on one side and between storage arrays and entities on the other side.
VM provisioning based on VM storage policies.
VMware Cloud Director uses the SPBM policies defined in vCenter Server. These policies are assigned to a Provider VDC and are available to Organization VDCs managed by the Provider VDC.
IOPS: You can enable the I/O operations per second (IOPS) setting for a storage policy so that tenants can set per-disk IOPS limits.
Managed read/write performance in physical storage devices and virtual disks is defined in units called IOPS, which measure read/write operations per second. To limit I/O performance, a provider VDC storage policy that includes storage devices with enabled IOPS allocation must back an organization VDC storage policy. Afterwards, a tenant can configure disks to request a specified level of I/O performance. A storage profile configured with IOPS support delivers its default IOPS value to all disks that use it. That includes disks that are not configured to request a specific IOPS value. A hard disk configured to request a specific IOPS value cannot use a storage policy whose maximum IOPS value is lower than the requested value, or a storage policy that is not configured with IOPS support.
You can edit the default IOPS settings. For example, you can set limits on IOPS per disk or IOPS per storage policy. You can set IOPS limits per disk based on the disk size in GB so that you grant more IOPS to larger disks. Tenants can set custom IOPS on a disk within these limits. You can use IOPS limiting with or without IOPS capacity considerations for placement.
You cannot enable IOPS on a storage policy backed by a Storage DRS cluster.
The storage policies are dependent on the workload being deployed, so generic design recommendations would be irrelevant. Instead, create storage policies based on the storage type and workload demands such that the vendor requirements are met.