Sub 5m Cables - Any reason to go optics versus DA Twinax?

[Jeggs101]

I'm starting the expensive process of buying cables for 10 and 40 gigE at home. Just a 14U rack so it's not like the cables need to span a mile or more.

I know that copper is easier to bend. What I'm looking for is some perspective on latency and power consumption of using copper versus short range optics.

 

[Chuckleb]

I don't think that copper latency is much of an issue or else IB would be fiber everywhere. The guys that have that gear are nuts and money is no object.

I am hoping my new gear comes in this week so I can start some copper testing. I am going to see if I can get the Brocade cards to talk to my Mellanox ConnectX3 using the QSFP breakout cables. If I can and can build a vswitch, will post results. This could be ideal for a small rack like you mention since 1 to 4 cables are cheap.

 

[mrkrad]

The cabling of DAC is a beast since the cables aren't as flexible, less pretty!

Also power consumption is higher and compatibility is questionable between certain brands; otherwise i've not had any issues except with 5Meter length, and the neatness of not being able to bend the cables as nicely as CAT6 or fiber OM3 cables.