Excluding vSAN, which has a specific configuration, at the physical level we can have three different main types of storage:

• Block-based storage acceded by a hardware adapter: This includes DAS storage or a SAN FC storage.
• Block-based storage acceded by a software adapter: This is like the SAN iSCSI storage when the software initiator is used. In this case, you need first to properly configure the network connectivity. After that, it becomes very similar to the first case.
• NFS storage: This is where you have to configure first the IP network connectivity to your storage and then connect the NFS datastore.

For the physical storage adapters, VMware ESXi supports several types of protocols and technologies (refer to the hardware compatibility list to check the supported level):

• Fibre Channel Host Bus Adapter (FC HBA): This is the common and historical way to implement an FC-based storage, but using a dedicated full fabric.
• iSCSI HBA: These are specialized PCIe cards that implement completely in hardware the entire iSCSI stack, reducing the load of the host CPU.
• CNA adapters for FCoE or iSCSI: These are mostly 10 Gbps (or greater) Ethernet adapters providing hardware (or hardware assisted) FCoE or iSCSI functionality on converged (or also dedicated) networks.
• RDMA over Converged Ethernet (RoCE): This is a network protocol that allows remote direct memory access (RDMA) over an Ethernet network. Starting with vSphere 6.5, RoCE certified adapters could be used for converged networks.
• InfiniBand HCA: Mellanox Technologies InfiniBand HCA device drivers are available directly from Mellanox Technologies. Mostly used for the network part instead of the storage part, they could be interesting in converged networks, and also in vSAN implementation.