Pretty sure my friend Cody Hosterman has talked about this until he turned blue in the face. Just a point I want to quickly re-iterate here for the record. Run unmap on your vSphere Datastores.
Read this if you are running Pure Storage, but even if you run other arrays (especially all-flash) find a way to do UNMAP on a regular basis:
Additionally, start to learn the ins-n-outs of vSphere 6 and automatic unmap!
Speaking of In-n-out…. I want a double double before I start Whole 30.