Fiber is fast enough to be used. Huawei got 3TBps transfer speeds over regular fiber just a couple of weeks ago
We have a couple of machines in a cluster at work, and they host 200 virtual machines.
All the storage for the VM's is located on two Dell EqualLogic SAN's. ALL the storage. 200 virtual computers (with a lot of workload) has all their storage (boot drives, file storage etc) located on these.
The machines and SANs are connected to a FC switch (8GBps). It's fast enough to keep 200 machines going for all their storage needs, so I'm very sure that it will be more than enough for recording audio to.
A 7200rpm drive (without any type of RAID array configured) works just fine to record 60 tracks at 24bit & 48khz at the same time on the faster ATA100 bus in the MDD. No need for RAID arrays. The bottleneck will always be the PCI bus and all the data on the tiny bus.
I for instance can't "bounce" a project in Pro Tools 5.1.3 to my boot drive. It will just choke in 3 seconds and complain about too much PCI activity. Bouncing to the same drive the project files are on works great, though. I guess it's because the data don't get moved around that much compared when bouncing from the project disk connected to the ATA100 connector, to the SSD connected to the ATA33 port. It clogs up the system.
This is when bouncing 60-track projects with 10 AUX sends, 3-4 plugins on every track and a lot of automations. So it's no hobby stuff