Is it possible to use Linux as a Fibre Channel Raid Disk Box?

SCST -- is a generic SCSI target subsystem for Linux (SCST) is an alternative implementation of a SCSI target subsystem for Linux. It provides unified, consistent interface between SCSI target drivers and Linux kernel as well as between Linux kernel and storage backend handlers, connecting target drivers with real or emulated storage backend.

SCST allows creation of sophisticated storage devices, which provide advanced functionality, like replication, thin provisioning, deduplication, high availability, automatic backup, etc. Another class of such devices are Virtual Tape Libraries (VTL) as well as other disk-based backup solutions. SCST created devices not limited by IP networking only. They can use any link which supports SCSI-style data exchange, including Fibre Channel, iSCSI, SAS, InfiniBand and parallel (Wide) SCSI. It might well be that your favorite storage appliance running SCST in the firmware.

Another way to do it is to use LIO Target: http://en.wikipedia.org/wiki/LIO_Target At this point, this is the solution that has been merged into the Linux mainline branch and support has been added to a number of distributions.