Hi Ryan –
first off, there are lots of companies, like Sonnet and Magma that make PCIe expansion chassis for any new Mac Pro that has Thunderbolt only, so you can stick all your cards into one of these chassis, and keep going. And of course, there are lots of companies that make Thunderbolt to Fibre adaptors (Promise SanLink) so you can continue to use what you are doing now.
There are lots of companies that make large Thunderbolt drive arrays (G-Tech, Promise, Maxx Digital,Netstor etc.) that can be used for shared storage.
When you say buying a Corning optical cable for $600 is expensive – that is the least of your expenses if you are considering buying a new large thunderbolt drive array, or new shared storage system, which will cost you a LOT of money.
You can absolutely have a shared storage system that uses Cat6 cable that will be FASTER than 4 or 8 Gig Fibre. There are lots of companies, like Facilis, Maxx Digital, Studio Network Solutions, Small Tree, ProMax, etc. that will be more than happy to sell you a wonderful very fast shared storage system that will connect via Cat6 cable and 10Gig Ethernet. These systems are readily available, and work wonderfully, and are much faster than anything you have previously owned.
The system described by Edgar is the Accusys Exasan system, which now offers Thunderbolt to QSFP adaptors, that can attach to new Mac Pro or iMac computers with thunderbolt, and attach to an Exasan switch via optical cable. The shared drive arrays which can be 8, 12 or 16 bay, also attach to the switch, and you can have up to 4 drive arrays with their system. Edgars solution works with Apple XSAN, but Accusys also works wonderfully with Tiger Technology Tiger Share, using the Tiger Serve 1, which will allow you to use easier to use client and admin software, without having to setup an XSAN system.
Let me be clear about one thing. The only things that WILL NOT WORK is by purchasing a new Mac Pro, and running Thunderbolt cables from the client computers to the new Mac Pro, and trying to do shared storage that way. This is the only combination that will not work. Thunderbolt networking DOES NOT WORK for your application.
If you find all of this confusing, all of the companies I mentioned in this post can help you. And so can I. Just reach out.
Bob Zelin
Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com