> On Sat, 22 Mar 2008, Patrick Giagnocavo wrote:
> > Would someone pay extra for > 7KW in a rack?
What would be the maximum you
> > could ever see yourself needing in order to power
all 42U ?
>
> As you recognize, its not an engineering question; its
an economic
> question. Notice how Google's space/power philosphy
changed between
> leveraging other people's space/power, and now that
they own their own
> space/power.
>
> Existing equipment could exceed 20kW in a rack, and
some folks are
> planning for equipment exceeding 30kW in a rack.
>
> But things get more interesting when you look at the
total economics
> of a data center. 8kW/rack is the new
"average," but that includes
> a lot of assumptions. If someone else is paying, I
want it and more.
> If I'm paying for it, I discover I can get by with
less.
That may not be the correct way to look at it.
There's a very reasonable argument to be made that the
artificial economic
models used by colocation providers has created this monster
to begin with.
The primary motivation for many customers to put more stuff
in a single
rack is that the cost for a rack subsidizes at least a
portion of the power
and cooling costs. A single rack with two 20A circuits
typically costs less
than two racks with a 20A circuit each. To some extent,
this makes sense.
However, it often costs *much* less for the single rack with
two 20A
circuits.
Charging substantially less for rack space, even offset by
higher costs for
power, would encourage a lot of colo customers to
"spread the load" around
and not feel as obligated to maximize the use of space.
That would in turn
reduce the tendency for there to be excessive numbers of hot
spots.
The economic question of how to build your pricing model
ultimately becomes
an engineering question, because it becomes progressively
more difficult to
provide power and cooling as density increases.
Or, to quote you, in an entirely different context:
> If I'm paying for it, I discover I can get by with
less.
The problem is that this is currently true for values of
"it" where "it"
equals "racks."
... JG
--
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me
one chance [and] then I
won't contact you again." - Direct Marketing Ass'n
position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way
too many apples.
|
40$ in facility B.
I can fit my 8 racks into either the 320sqft or into the
800. If I'm
doing the 800, I'll probably spend a bit more up front and
use 12 or 14
racks, to keep my density down. A bit more cost up front,
but in the
grand scheme of things 4 or 6 extra racks ($6 to 10,000$)
don't directly
hurt to much. (80kW worth of power usually means you've got
well north of
$2M worth of hardware and software being stuffed into the
space in my
experience..but maybe that's because we're an Oracle shop.
;)
Of course, I suppose for those customers still doing
super-low-density
boxes (webhosting with lots and lots of desktops), I suppose
that model
wouldn't work as well.
ramble.
.d
---
david raistrick 