[Bob Zelin] "If you have a Mac Mini, and the Promise Thunderbolt to Fibre adaptor (non yet released) - can you run an XSAN enviornment - or do you have to to the WHOLE EXPENSIVE COMPLEX THING - with the 2 servers, dual switches, plus fibre cards in every MAC Pro, no iMAC's, no MacMini clients, no MacBook Pro clients ? None of this is made clear. "
Short answer: it has to stay complicated.
Long answer: Xsan is essentially StorNext, and for a client to participate in a StorNext filesystem, the fibre channel switching is essential. Xsan probably won't let you, but StorNext can actually make a SNFS filesystem on internal disks. But if you want more than the MDC to be able to access the filesystem as well, that's where the switch comes in. Xsan/StorNext clients need block-level access to the disk for it to work. The only way to get multiple clients seeing disk at the block level is via switched block-level protocols like fibre channel.
[Bob Zelin] "The idea of having to buy a Promise VTrak, dual servers, Fibre cards for every MAC Pro, and a QLogic Fibre switch kind of defeats the purpose of a "simple" SAN from Apple."
You don't need redundant MDCs to run an Xsan filesystem, but redundant MDCs is the de facto standard install. Every client does need to have a fibre channel HBA of some kind (be it a card or a Thunderbolt adapter). The most complicated part of Xsan by far is the FC switch.
[Bob Zelin] "And as this forum demonstrates on a daily basis - there are LOTS AND LOTS of simple, easy to use, and inexpensive SAN's already out there."
It's hair-splitting, but some of the "SANs" you're referring to are really
NAS. Technically, Xsan is a
shared disk clustered filesystem atop a SAN.
But for video editing purposes, none of that really matters. Video editing doesn't require block-level access to work. File-level access via TCP protocols works just fine as long as the bandwidth is there.
[Bob Zelin] "So what secret (if any) is up Apple's sleeve ? "
I too am puzzled about Apple's strategy for Xsan. It pretty much
can't be dead simple due to the required infrastructure for that type of SAN, but now they are giving the software away with Lion. Thunderbolt makes it possible to physically connect to Xsan with iMacs, Mac minis, and MacBooks, but that doesn't make it easy- you still have to set up and zone a very complicated fibre switch. What's up their sleeve? The magic eight ball says "cannot predict now".
Best,
Andy
