What protocol can Riya use to connect her external storage area network device to Windows Server 2019?

The most appropriate protocol for Riya to connect her external storage area network (SAN) device to Windows Server 2019 is iSCSI. iSCSI, which stands for Internet Small Computer Systems Interface, allows the transmission of SCSI commands over a TCP/IP network. This is particularly useful for connecting storage devices, as it enables them to be accessed over a network as if they were local disks.

iSCSI is specifically designed for SAN implementations, allowing multiple servers to share the storage resources effectively. Windows Server 2019 has built-in support for iSCSI, making it an ideal choice for managing remote storage connected over a network.

While other protocols like SMB (Server Message Block), FTP (File Transfer Protocol), and NFS (Network File System) do facilitate file sharing and data transfer, they do not serve the same function as iSCSI in the context of connecting to a SAN. SMB is primarily used for sharing files and printers in a Windows environment, FTP is typically employed for transferring files, and NFS is more commonly used in Unix/Linux environments for file sharing. Therefore, for the specific purpose of connecting an external SAN device to Windows Server 2019, iSCSI is the most suitable and effective protocol to use.