The primary source of storage for Cloud Foundation is vSAN. For example, a 1U server can have 8 disks in the capacity tier and 2 disks in the caching tier. All disks are claimed by vSAN for storage.
The amount of available physical storage in workload domains depends on the number of physical hosts. The amount of usable capacity depends on availability requirements.
Storage traffic is carried over the 10Gbps links between the hosts and ToR switches. There is a dedicated vSAN port group defined on the vDS. All vSAN members communicate over this 10 Gbps network.
vSphere Network I/O Control (NIOC) can be enabled to allow network resource management to use network resource pools to prioritize network traffic by type.