Storage Policy Based Management (SPBM) is relatively new to the vSphere world. It got introduced with vSphere 5.0 and has been quite enhanced since then. The basic principle of SPBM is to manage the storage in form of VMFS data stores based on precreated policies instead of trying to figure out their function by their name.
Typically, organizations picked a distinct name scheme to apply to the data stores to identify their capabilities. Such a name could look like:
This is a code to identify what this VMFS data store has to offer. Translated it means:
S1= site 1
DR= disaster recovery/replicated data store
040=LUN ID to identify in ESXi/storage system
All the admins have to know all this abbreviations ...