[bjames]

Will a 4 gbit dual fibre channel disk array (stone) work when it connected to the octane dual 1 gbit fibre  channel XIO option board?

For flame 2008sp6

[waldemar72]

It should work. Fibre channel provides 3 generations back compatibility, so 4Gb is compatible with 1Gb. Cabling is another story. XIO Sgi card has copper connections and 4Gb are only available as optical or SFP connctions. So you will need at least MIA adapters for copper connectors of xio card to convert signal to optical and of course optical cord to connect it to array. Sure the whole thing will run only 1Gb per channel (limited to slowest part, e.g. XIO sgi card).

[HAL]

Yes,

later ip35-related gear like O3x0/O3x00/Fuel/Tezro support pci-x adapters from LSI or Qlogic supporting up the 4gbit/s.
The Fuel-wiki lists some of them, but not all.

http://wiki.irix.cc/Fuel

The Octane though does support only max. 2gbit/s adapters iirc. Even the O2 supports a FC-HBA.

[jan-jaap]

what do you suggest for the Octane's shoebox?

QLA2342, dual 2Gb/s, PCI-X. Cheap and plentiful, and they work out of the box.

FWIW, the bandwidth of the XIO-PCI bridge in the shoebox (which is shared by all three PCI slots) is ~ 160MB/s, so even a single QLA2342 will more than saturate it. If you put a QLA2342 and a dual Gbit ethernet board in a single PCI shoebox and expect 200MB/s transfers to the network you'll be disappointed.

[Titox]

I don't think you can mix different speed GBICS. May be you have to put 1Gb transceivers on your stone arrays to get them working with the Octane 1Gb card.

If I recall correctly in Fiber optics there is not speed negotiation like you have in cooper connections.

[jpstewart]

If I recall correctly in Fiber optics there is not speed negotiation like you have in cooper connections.

It might depend on the hardware. 

Certainly my Brocade switches auto-negotiate each port to 4/2/1 Gbit/sec without having having to change SFPs.  The 8 Gbit/sec PCIe cards in two of my systems auto-negotiate down to 4 Gbit/sec when connected to the switch or to a 4 Gbit/sec array controller.

That said, I also have an HP M6412A enclosure that's meant to be used with an EVA x400-series array controller and it is a fixed 4 Gbit/sec link with no speed negotiation (that I'm aware of).  Connecting it to a 2 Gbit/sec host does not work.  Connecting at 4 Gbit/sec works whether it is to the matching array controller, directly to a host, or through a switch.