[Arm-netbook] EOMA server standard

[luke.leighton]

On Wed, Oct 24, 2012 at 8:53 AM, Gordan Bobic <gordan at bobich.net> wrote:
> On 10/23/2012 06:09 PM, luke.leighton wrote:
>> ok, right.  i've been talking to some companies and the need for a
>> standard which covers data centres - e.g. has 10Gigabit Ethernet - has
>> come up.
>>
>> it turns out that 10GBase-T is 500mhz and 16-way PAM over each of the
>> 2-twisted-pairs that go onto a standard RJ-45.  so, *fast*, but also
>> staggeringly power-hungry.  this 10GBase-T PHY IC has one variant at
>> 2.4 watts and another at 6 watts:
>>     http://www.solarflare.com/Ethernet-Controllers-LOMs
>>
>> so the question i'm raising is: what would people see as being the
>> most appropriate general-purpose and lowest-common-denominator
>> "upgradeable" interfaces to have on an EOMA standard?  and, what case
>> would be good to re-use?
>>
>> for the pin-outs i figured that at least one 10GBase-T interface (8
>> pins plus 8 GND spacers) would be acceptable, as would SATA-3 (4 pins
>> plus 4 GND spacers).  that's 24 pins already (!).  PCI-Express 4x is
>> 64 pins.  that's up to 88 *already*.  adding in USB3, it's not
>> unreasonable to imagine this would be a 100-pin standard.
>>
>> so this is going to need some really careful thought.
>
> Why on earth would anyone in the right state of mind even consider
> running 10G ethernet over copper?

 *lol* i don't know!  preexisting infrastructure (racks) maybe?

> Every deployment I have seen to date is fibre based. 10G copper switches don't sound particularly plausible
> if you have to vent out 6W of heat per port.

 that makes sense.  yeah.  5W processor; an extra 6W on the port.  duh.

> If fibre is not an option for the chassis for some obscure reason,
> multiple gigabit connections (you have to have a built in gigabit switch
> anyway for each node) are a much more sensible option than 10Gb copper,
> and much cheaper and more versatile than fibre.

 hmmm...  ok.  that makes sense.  thanks gordan.

l.