If you use vCenter Server to manage your ESX/ESXi hosts, you can review information on storage usage and visually map relationships between all storage entities available in vCenter Server.

In the vSphere Client, for any inventory object except networking, the storage usage data appears in the Storage Views tab. To view this tab, you must have the vCenter Storage Monitoring plug-in, which is generally installed and enabled by default.

You can display storage information as reports or storage topology maps.

Reports

Reports display relationship tables that provide insight about how an inventory object is associated with storage entities. They also offer summarized storage usage data for the object’s virtual and physical storage resources. Use the Reports view to analyze storage space utilization and availability, multipathing status, and other storage properties of the selected object and items related to it.

Maps

Maps display storage topology maps that visually represent relationships between the selected object and its associated virtual and physical storage entities.

For more information on virtual and phisical storage resources and how virtual mahcines access sotrage, see ESX Configuration Guide or ESXi Configuration Guide.