[HH] Has anyone seen a solution to this?

[Tom Metro]

Kurt Keville wrote:
> ...I want the head node to have 6
> connections directly to the hard drives... I figure this would
> require some sort of SATA pigtail in the client nodes, and a 6
> node SATA card in the head node...

It sounds like you are describing having a 2-to-1 Y-cable connecting to
each hard drive, where each drive is under control of two hosts. Am I
understanding that correctly?

Never mind the software challenges, I'm not sure you can pull that off
electrically. SATA is a high-speed serial bus, which is going to be
sensitive to cable termination and require active electronics to combine
signals from both hosts. Have you seen an off-the-shelf device to do that?

There are SATA multiplexer chips, but they typically are designed to
expand one host port into multiple device ports. You're looking to do
the opposite.


> Well the first batch of nodes we are going to try this with are the
> Jetson TK1s...  
> http://www.nvidia.com/object/jetson-tk1-embedded-dev-kit.html    ...
> there aren't a lot of I/O options and we have already tested the onboard
> GigE and found it to be lacking in a couple of areas.

What about USB3? What about the "Half Mini-PCIE Slot?" Or the SD/MMC
Connector?

Any of those should get you high-bandwidth I/O, with USB3 being the
easiest to link up using off-the-shelf gear. Or you can get GigE
Mini-PCIE Ethernet cards for $15:
http://www.amazon.com/s?ie=UTF8&page=1&rh=i%3Aaps%2Ck%3Amini%20pci%20ethernet%20card

 -Tom