Apple's Xsan was the Storage Area Network for Final Cut Pro. But what exactly is Xsan?
Xsan is the Apple software that allows you to connect to a StorNext file system on a Mac.
Interestingly, Apple built XSAN software to connect to StorNext file systems which, at the time, was owned by Advanced Digital Information Corporation, or ADIC.
A year after Apple released Xsan, Quantum acquired ADIC and to this day still uses the same code base for their SAN.
Xsan, still exists and it's still the software that allows Mac workstations to connect to StorNext file systems. However, today, it is just part of the Mac OS.