LUNs are the basic unit of storage in a SAN configuration. The Windows host sees LUNs on your storage system as virtual disks.
More information
LUN overview
You can use a LUN the same way you use local disks on the host.
Initiator group overview
Initiator groups (igroups) specify which hosts can access specified LUNs on the storage system. You can create igroups manually, or you can use the optional SnapDrive for Windows software, which automatically creates igroups.
About FC targets
The host automatically discovers FC targets that are accessible to its HBAs. However, you do need to verify that the host selects only primary (optimized) paths to FC targets.
Accessing LUNs
To access LUNs when you are using the iSCSI protocol, you must add an entry for the storage system using the iSCSI Initiator Properties dialog box on the host.