The iSCSI target (server)
The iSCSI target is a software that makes disk space available on a network. This service shares disks rather than filesystems and establishes a Storage Area Network (SAN). This SAN storage can be used so that servers can share same disks, a situation that is often required where other network services are clustered and need access to shared disks on the network. It's usual that only one server will have access to each shared disk at any one time. The iSCSI target can share complete disks, but it's often more efficient to share the exact space required by the client through logical volumes implemented with LVMs. As well as sharing block devices, it's also possible to create files and share the file space as disks through the target server.
The disk IO passes through standard network connections to iSCSI servers. So, the faster the network connection, the better the storage performance. Although iSCSI will work on 1 GB Ethernet networks, 10 GB Ethernet is preferred...