North American Network Operators Group|
Date Prev | Date Next |
Date Index |
Thread Index |
Author Index |
Re: rack power question
- From: Marshall Eubanks
- Date: Mon Mar 24 01:14:21 2008
The interesting thing is how in a way we seem to have come full
circle. I am sure lots of people can remember large rooms
full of racks of vacuum tube equipment, which required serious power
On one NASA project I worked on, when the vacuum tube stuff was
replaced by solid state in the late 1980's,
there was lots of empty floor space and we marveled at how much power
we were saving. In fact, after
the switch there was almost 2 orders of magnitude too much cooling
for the new equipment (200 tons to 5 IIRC),
and we had to spend good money to replace the old cooling system with
a smaller one. Now, we seem to have expanded
to more than fill the previous tube-based power and space
requirements, and I suspect some people wish they could get
their old cooling plants back.
On Mar 23, 2008, at 5:23 PM, Joel Jaeggli wrote
Ben Butler wrote:
There comes a point where you cant physically transfer the energy
any more - not less you wana break the laws a physics captin
resist sorry) - to your DX system, gas, then water, then in rack
cooling, water and CO2. Sooner or later we will sink the hole
room in oil,
much like they use to do with Cray's.
The problem there is actually the thermal gradient involved. the
fact of the matter is you're using ~15c air to keep equipment
cooled to ~30c. Your car is probably in the low 20% range as far
as thermal efficiency goes, is generating order of 200kw and has an
engine compartment enclosing a volume of roughly half a rack... All
that waste heat is removed by air, the difference being that it
runs a around 250c with some hot spots approaching 900c.
Increase the width of the thermal gradient and you can pull much
more heat out of the rack without moving more air.
15 years ago I would have told you that gallium arsenide would be a
lot more common in general purpose semiconductors for precisely
this reason. but silicon has proved superior along a number of
Alternatively we might need to fit the engineers with crampons,
ropes and ice axes to stop them being blown over by the 70 mph
winds in your
datacenter as we try to shift the volumes of area necessary to
energy back to the HVAC for heat pump exchange to remote chillers
In my humble experience, the problems are 1> Heat, 2> Backup UPS,
Generators, 4> LV/HV Supply to building.
While you will be very constrained by 4 in terms of upgrades
a lot of money to upgrade - the practicalities of 1,2&3 mean that
have spent a significant amount of money getting to the point
where you need
to worry about 4.
Given you are not worried about 1, I wonder about the scale of the
application or your comprehension of the problem.
The bigger trick is planning for upgrades of a live site where you
increase Air con, UPS and Generators.
Economically, that 10,000KW of electricity has to be paid for in
any charge for the rack space. Plus margined, credit risked and cash
flowed. The relative charge for the electricity consumption -
less about our ability to deliver and cool it in a single rack
cost of having four racks in a 2,500KW datacenter and paying for
amount of electric. Is the racking charge really the significant
For the sake of argument, 4 racks at £2500 pa in a 2500KW
datacenter or 1
rack at £10,000 pa in a 10000KW datacenter - which would you
Is the cost of delivering (and cooling) 10000KW to a rack more or
400% of the cost of delivering 2500KW per rack. I submit that it
that 400%. What about the hardware - per mip / cpu horse power am
more or less in a conventional 1U pizza box format or a high
format - I submit the blades cost more in Capex and there is no
What is the point having a high density server solution if I can
fill the rack.
I think the problem is people (customers) on the whole don't
problem and they can grasp the concept of paying for physical
cant wrap their heads around the more abstract concept of electricity
consumed by what you put in the space and paying for that to come
up with a
TCO for comparisons. So they simply see the entire hosting bill and
conslude they have to stuff as many processors as possible into
space and if that is a problem is is one for the colo facility to
the same price.
I do find myself increasingly feeling that the current market
simply stupid and had far to much input from sales and marketing
Let alone the question of is the customers business efficient in
the amount of CPU compute power required for their business to
of customer sales/revenue.
Just because some colo customers have cr*ppy business models
marginal benefit for very high computer overheads and an inability
for things in a manner that reflects their worth because they are
of extracting the value from them. Do we really have to drag the
industry down to the lowest common denominator of f*ckwit.
Surly we should be asking exactly is driving the demand for high
computing and in which market sectors and is this actually the best
technical solution to solve them problem. I don't care if IBM, HP
want to keep selling new shiny boxes each year because they are
we need them - do we really? ...?
From: [email protected] [mailto:[email protected]] On
Sent: 23 March 2008 02:34
To: Patrick Giagnocavo
Cc: [email protected]
Subject: Re: rack power question