iSCSI
also: Internet SCSI, SCSI over TCP/IP
iSCSI (Internet SCSI) is a network protocol that allows computers to send SCSI storage commands over standard IP networks, enabling remote block-level storage access as if the storage were locally attached.
iSCSI extends the SCSI protocol—traditionally used for direct-attached storage—over TCP/IP networks. This lets a client machine (initiator) communicate with a remote storage server (target) and use network-attached storage as if it were a local disk.
An iSCSI initiator sends read/write commands over the network to an iSCSI target, which manages the actual storage devices. The storage appears to the operating system as local block devices (like /dev/sda), making it transparent to applications.
Example: A Linux server can boot from or mount a remote iSCSI target using tools like open-iscsi, treating gigabytes of network storage as local drives. This is widely used in data centers and enterprise environments for centralized storage management.