Why is centralized storage so important for enterprise virtualization products?
Centralized storage (such as an iSCSI or FC SAN) is very critical to many optional virtualization features. For example, with VMware High Availability (VMHA), VMs are stored in a centralized shared data store. If an ESX Server goes down, those VMs are automatically restarted on another ESX host because that host can access them overt the centralized shared storage (SAN). Thus, while centralized storage isn’t required to use enterprise virtualization features, many of the advanced or optional virtualization features don’t work without it.