not SAN
at least not in the traditional sense. This article reads like you are building your own storage system I see no mention of something simple like high availability, or reliability, or replication, online upgrades, caching, storage system architecture, or the multitude of other software/hardware capabilities that modern storage systems offer.
For some folks building their own is the way to go, though for most it is probably not the best idea. Something as simple as firmware (and firmware upgrades) on the storage media can pose quite a problem.
The last time I had to deal with firmware issues on HDDs was about 6 years ago, on Dell servers, and the only way to upgrade the firmware was for someone to go to the server and boot with a DOS boot disk (the firmware didn't even have a changelog we upgraded them as a last resort to try to fix a performance issue and it turned out it worked).
My systems since have been boot from SAN(with only a handful of exceptions), so I haven't had to worry about firmware, the storage system upgrades it for me in the background.