RE: Why choose 120 volts?

[Alex Rubenstein]

> > Even better would be all two pole 2 pole 480's or 2 pole 600's, then
> > we wouldn't need neutrals.
> 
> Oh, yeah! Nothing sounds like more fun than working in a room full of
> 480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
> have a functioning heart.)

Nobody said delta.

Re: AH or ESP

[Roland Dobbins]

On May 27, 2009, at 3:00 AM, Tony Hain wrote:

Just because you can't use it for IPv4 is no reason to avoid using  
it for IPv6 now and let its momentum suppress the 66CGN walled  
garden mindset.


I concur quite strongly with your views on this particular topic, but  
the CGN boat appears to've sailed, AFAICT.


---
Roland Dobbins  // 

Unfortunately, inefficiency scales really well.

   -- Kevin Lawton

RE: Why choose 120 volts?

[telmnstr]

Oh, yeah! Nothing sounds like more fun than working in a room full of
480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
have a functioning heart.)

Nobody said delta.


If you just run 7200vac into your 1u chinese made peecee servers, then you 
can eliminate the space use of the step-down transformer in the mechanical 
room.

Re: Why choose 120 volts?

[Wayne E. Bouchard]

1) Equipment used to not be dual voltage

2) For smaller scale, 120V UPS and distribution equipment is usually
cheaper

3) 120V embedded itself into operations as a result.

4) We're all lazy and hate change.

On Tue, May 26, 2009 at 12:39:10PM -0700, Seth Mattinen wrote:
> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?
> 
> I've been running my facility at 208 for years because I can get away
> with lower amperage circuits. I'm curious about the reasons for using
> high-amp 120 volt circuits to drive racks of equipment instead of
> low-amp 208 or 240 volt circuits.
> 
> ~Seth

---
Wayne Bouchard
w...@typo.org
Network Dude
http://www.typo.org/~web/

RE: Why choose 120 volts?

[Kurt Anderson]

Why stop there? Grab a 20,000 volt feeder and create a Tesla datacenter.
Think of all the copper you will save...

-Original Message-
From: telmn...@757.org [mailto:telmn...@757.org] 
Sent: Tuesday, May 26, 2009 3:16 PM
Cc: nanog@nanog.org
Subject: RE: Why choose 120 volts? 

>> Oh, yeah! Nothing sounds like more fun than working in a room full of
>> 480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
>> have a functioning heart.)
> Nobody said delta.

If you just run 7200vac into your 1u chinese made peecee servers, then
you 
can eliminate the space use of the step-down transformer in the
mechanical 
room.

Re: MX Record Theories

[gb10hkzo-nanog]

Hi,

> I thought i'd give you a quick response (and welcome to NANOG) :).

Thanks.

I can't believe that I've already received three very interesting responses in 
just over an hour !

I've been quietly lurking on NANOG for a while, just plucked up the courage to 
post . and might now even find a bit more courage to attempt to contribute 
to some threads !

Glad to see the community spirit still exists !

Keep the replies coming if there are any still on their  way . :)


Tim


P.S. Valdis Kletnieks . I've got the feeling that this 

>  That 507 is critically important

if it's true, might potentially explain a few intermittent unexplicable issues 
we've been seeing at some sites  time for some research me thinks :)

Re: Why choose 120 volts?

[Barney Wolff]

Doesn't even need non-standard servers - just wire them all in series.

On Tue, May 26, 2009 at 03:23:46PM -0500, Kurt Anderson wrote:
> Why stop there? Grab a 20,000 volt feeder and create a Tesla datacenter.
> Think of all the copper you will save...

Re: Why choose 120 volts?

[Andy Ringsmuth]

On May 26, 2009, at 3:29 PM, Barney Wolff wrote:


On Tue, May 26, 2009 at 03:23:46PM -0500, Kurt Anderson wrote:
Why stop there? Grab a 20,000 volt feeder and create a Tesla  
datacenter.

Think of all the copper you will save...


Oh, c'mon people!  We need to all think green here too.  All you need  
is to locate it in the right spot on the planet and set up a big  
lightning rod.  The first sustainable energy datacenter with no  
emissions!



-Andy

Re: Why choose 120 volts?

[Ray Sanders]

So when one server fails, all the rest fail too? 

Sorting out holiday lighting is bad enough 

could you imagine having to go through rack after rack finding the one
"burned out" server?


On Tue, 2009-05-26 at 16:29 -0400, Barney Wolff wrote:
> Doesn't even need non-standard servers - just wire them all in series.
> 
> On Tue, May 26, 2009 at 03:23:46PM -0500, Kurt Anderson wrote:
> > Why stop there? Grab a 20,000 volt feeder and create a Tesla datacenter.
> > Think of all the copper you will save...
> 
-- 
"Prediction is very difficult, especially about the future." Niels Bohr
--
Ray Sanders
Linux Administrator
Village Voice Media
Office: 602-744-6547
Cell: 602-300-4344

RE: Why choose 120 volts?

[Dave Larter]

It will be like at Christmas time, trying to find the bad bulb. 

-Original Message-
From: Barney Wolff [mailto:bar...@databus.com] 
Sent: Tuesday, May 26, 2009 4:29 PM
To: nanog@nanog.org
Subject: Re: Why choose 120 volts?

Doesn't even need non-standard servers - just wire them all in series.

On Tue, May 26, 2009 at 03:23:46PM -0500, Kurt Anderson wrote:
> Why stop there? Grab a 20,000 volt feeder and create a Tesla
datacenter.
> Think of all the copper you will save...

Re: Why choose 120 volts?

[Joe Greco]

> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?
> 
> I've been running my facility at 208 for years because I can get away
> with lower amperage circuits. I'm curious about the reasons for using
> high-amp 120 volt circuits to drive racks of equipment instead of
> low-amp 208 or 240 volt circuits.

208 isn't all that great.  On one hand, a 20A 208V circuit is vaguely
more convenient than a 30A 120V circuit because it is delivering a bit
more power to the rack (3328 vs 2880), and it's likely to work with a
lot of modern equipment containing autoranging power supplies.

On the flip side, with 120, you don't have to have "odd cords," and it
is somewhat easier to "right-size" power for a rack (20A, 30A, 2x20A),
so for an average rack that isn't crammed with high power webhosting
1U's (etc), a customer might actually find that the ability to right-
size the power feed is more flexible with 120V.

And I don't like not having anywhere to plug in my power screwdriver's
recharger...  I suppose I should see if I can find someplace that has
a transformer of an appropriate size, or does anyone already have the
part number for something that can provide a few hunderd milliamps of
120V from 208?  :-)

... 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.

Re: Why choose 120 volts?

[Joe Greco]

> It will be like at Christmas time, trying to find the bad bulb. 

This sounds like an opportunity for you guys to find "that special
tool" everyone needs, and sell it to all of us.  ;-)

(Dave's with Stayonline, and if you haven't been to his company's web
site, they're full of wonderful odds and ends ... at a bit of a mark-
up.)

... 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.

Re: Why choose 120 volts?

[Owen DeLong]

On May 26, 2009, at 1:34 PM, Ray Sanders wrote:


So when one server fails, all the rest fail too?

Sorting out holiday lighting is bad enough

could you imagine having to go through rack after rack finding the one
"burned out" server?


Who has to imagine?  Some of us remember thinnet (10base2).

Owen

RE: Why choose 120 volts?

[Aaron Wendel]

Our power is handed to us at 480v.  We then deliver it to the customer at 
whatever they need.  The nice thing about 120v is that everything uses it.  No 
odd cords (as mentioned before) or expensive PDUs.

I've had a lot of people suggest that running our servers at 240v would save us 
money because we'd use less amps.  Last time I looked at my bill I was being 
billed by the kWh, not amp and 240v at half the amps is still the same wattage. 
 I've been told this so many times though that I'm starting to doubt myself.  
If anyone can present a reason for me to switch to 240v I'd like to hear it.

Aaron


-Original Message-
From: Seth Mattinen [mailto:se...@rollernet.us] 
Sent: Tuesday, May 26, 2009 2:39 PM
To: nanog@nanog.org
Subject: Why choose 120 volts?

I have a pure curiosity question for the NANOG crowd here. If you run
your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get away
with lower amperage circuits. I'm curious about the reasons for using
high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits.

~Seth

Re: Why choose 120 volts?

[Alex H. Ryu]

Also, adding followings.

5) availability from local power provider(s)

6) local regulation such as fire department safety rules...

7) for your own safety... (120V may not kill people, but 240V can do...)


If you want better, why not just have everything to DC power ?
Something like 48V...

Alex


Wayne E. Bouchard wrote:
> 1) Equipment used to not be dual voltage
>
> 2) For smaller scale, 120V UPS and distribution equipment is usually
> cheaper
>
> 3) 120V embedded itself into operations as a result.
>
> 4) We're all lazy and hate change.
>
> On Tue, May 26, 2009 at 12:39:10PM -0700, Seth Mattinen wrote:
>   
>> I have a pure curiosity question for the NANOG crowd here. If you run
>> your facility/datacenter/cage/rack on 120 volts, why?
>>
>> I've been running my facility at 208 for years because I can get away
>> with lower amperage circuits. I'm curious about the reasons for using
>> high-amp 120 volt circuits to drive racks of equipment instead of
>> low-amp 208 or 240 volt circuits.
>>
>> ~Seth
>> 
>
> ---
> Wayne Bouchard
> w...@typo.org
> Network Dude
> http://www.typo.org/~web/
>
>
>
>   

Re: Why choose 120 volts?

[Ray Sanders]

Ugh, please don't remind me of the hell that was coax. 

On Tue, 2009-05-26 at 13:45 -0700, Owen DeLong wrote:
> On May 26, 2009, at 1:34 PM, Ray Sanders wrote:
> 
> > So when one server fails, all the rest fail too?
> >
> > Sorting out holiday lighting is bad enough
> >
> > could you imagine having to go through rack after rack finding the one
> > "burned out" server?
> >
> Who has to imagine?  Some of us remember thinnet (10base2).
> 
> Owen
> 
-- 
"Prediction is very difficult, especially about the future." Niels Bohr
--
Ray Sanders
Linux Administrator
Village Voice Media
Office: 602-744-6547
Cell: 602-300-4344

RE: Why choose 120 volts?

[Gregory Hicks]

> Subject: RE: Why choose 120 volts? 
> Date: Tue, 26 May 2009 15:23:46 -0500
> From: "Kurt Anderson" 
> To: 
> 
> Why stop there? Grab a 20,000 volt feeder and create a Tesla
> datacenter.  Think of all the copper you will save...

Boy!  This thread went south in a hurry!  I about died laughing.
> 
> -Original Message-
> From: telmn...@757.org [mailto:telmn...@757.org] 
> Sent: Tuesday, May 26, 2009 3:16 PM
> Cc: nanog@nanog.org
> Subject: RE: Why choose 120 volts? 
> 
> >> Oh, yeah! Nothing sounds like more fun than working in a room full of
> >> 480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
> >> have a functioning heart.)
> > Nobody said delta.
> 
> If you just run 7200vac into your 1u chinese made peecee servers, then
> you 
> can eliminate the space use of the step-down transformer in the
> mechanical 
> room.
> 
> 
> 

-
Gregory Hicks   | Principal Systems Engineer
| Direct:   408.569.7928

People sleep peaceably in their beds at night only because rough men
stand ready to do violence on their behalf -- George Orwell

The price of freedom is eternal vigilance.  -- Thomas Jefferson

"The best we can hope for concerning the people at large is that they
be properly armed." --Alexander Hamilton

Re: AH or ESP

[Dave Israel]

Tony Hain wrote:
> Merike Kaeo wrote:
> ...
>   
>>   ESP-Null came about when folks
>> realized AH could not traverse NATs.
>> 
>
> Thus the absolute reason why people should promote AH to kill off the 66nat
> nonsense. Just because you can't use it for IPv4 is no reason to avoid using
> it for IPv6 now and let its momentum suppress the 66CGN walled garden
> mindset. 
>
>   

That should make for a fascinating discussion.

"You should use AH."
"Why?"
"So you can't use NAT."
"Any other reason?"
"... No."
"Great.  I'll get right on that."

The delusion that network operators can successfully use unhelpful
protocols and/or smoke and mirrors to force idealist network design on
others needs to end.  People use new protocols because they are better. 
If  the benefit of moving to a new protocol does not outweigh the pain
of moving to it, people don't use it.  That's why the OSI protocols did
not kill IP like they were supposed to in the 90s, it is why the largely
forgotten mandated move from Windows to secure OSes (ie, Unix) for all
government employees never happened, and it is why IPv6 is sputtering. 
If people want to use NAT, they are going to use NAT.  They may stop
using it if the widespread adoption of peer to peer protocols means they
are missing out on things other people are doing.  They are not going to
stop using NAT to use a protocol maliciously designed to break it; they
will just wait, patiently and nearly always successfully, for somebody
to come out with a version that has no such malice.  They are certainly
not going to stop using NAT because somebody tells them they should use
a security protocol that does not secure anything worth securing.

BitTorrent is a better anti-NAT tool than AH ever will be.  More carrot,
less stick.

-Dave

Re: Why choose 120 volts?

[Alex H. Ryu]

I still have a couple of Ethernet cards for 10Base2, and cables. ^.^
Yes, if someone unplug or it is loosen in the middle/end, it will be fun.
I guess it's going to be another bagel/coffee time except network
support people.

Alex


Ray Sanders wrote:
> Ugh, please don't remind me of the hell that was coax. 
>
> On Tue, 2009-05-26 at 13:45 -0700, Owen DeLong wrote:
>   
>> On May 26, 2009, at 1:34 PM, Ray Sanders wrote:
>>
>> 
>>> So when one server fails, all the rest fail too?
>>>
>>> Sorting out holiday lighting is bad enough
>>>
>>> could you imagine having to go through rack after rack finding the one
>>> "burned out" server?
>>>
>>>   
>> Who has to imagine?  Some of us remember thinnet (10base2).
>>
>> Owen
>>
>> 

RE: Why choose 120 volts? When DC will do

[John Lee]

What is all this talk about AC. Real data centers use DC. 

John (ISDN) Lee

From: Seth Mattinen [se...@rollernet.us]
Sent: Tuesday, May 26, 2009 3:39 PM
To: nanog@nanog.org
Subject: Why choose 120 volts?

I have a pure curiosity question for the NANOG crowd here. If you run
your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get away
with lower amperage circuits. I'm curious about the reasons for using
high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits.

~Seth

Re: Why choose 120 volts? When DC will do

[Warren Bailey]

I second that!

- Original Message -
From: John Lee 
To: Seth Mattinen ; nanog@nanog.org 
Sent: Tue May 26 12:56:42 2009
Subject: RE: Why choose 120 volts? When DC will do

What is all this talk about AC. Real data centers use DC. 

John (ISDN) Lee

From: Seth Mattinen [se...@rollernet.us]
Sent: Tuesday, May 26, 2009 3:39 PM
To: nanog@nanog.org
Subject: Why choose 120 volts?

I have a pure curiosity question for the NANOG crowd here. If you run
your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get away
with lower amperage circuits. I'm curious about the reasons for using
high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits.

~Seth

Re: Why choose 120 volts?

[Jay Hennigan]

Aaron Wendel wrote:

Our power is handed to us at 480v.  We then deliver it to the customer at 
whatever they need.  The nice thing about 120v is that everything uses it.  No 
odd cords (as mentioned before) or expensive PDUs.

I've had a lot of people suggest that running our servers at 240v would save us 
money because we'd use less amps.  Last time I looked at my bill I was being 
billed by the kWh, not amp and 240v at half the amps is still the same wattage. 
 I've been told this so many times though that I'm starting to doubt myself.  
If anyone can present a reason for me to switch to 240v I'd like to hear it.


Some servers (HP/Compaq comes to mind) and Cisco switches have 
limitations in terms of performance and/or capacity on 120v circuits.
Yes, it all gets crunched down to 5VDC and similar low voltages in the 
power supply.  The limitation is likely due to the gauge of wire used 
and copper losses in the input circuitry.  Higher current connectors and 
switches, larger copper conductors, etc. are costly.  If you have an 
application that needs that kind of power, higher voltages make sense.


This is just as true if the application is a server as it is if it's an 
electric stove or clothes dryer.


Most of the rest of the world has 240v as conventional domestic power, 
and most server rooms or datacenters supporting >2KVA single devices 
have 208 or 240v available, so it makes sense for manufacturers of 
high-power gear to save the money on copper and connectors and insist on 
higher input voltages for full spec output.


Yes, it would be nice to be able to plug in your laptop charger, etc. 
And the voltage on that charger is likely compatible with anything from 
100 to 240V.  Wiring a NEMA 5-15 with 208V is just wrong, though.  I 
have an IEC male to NEMA 5-15 female pigtail (old-school "monitor cord") 
with a big sticker saying "208V - Be very careful what you plug in here" 
for just that purpose.


--
Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net
Impulse Internet Service  -  http://www.impulse.net/
Your local telephone and internet company - 805 884-6323 - WB6RDV

Re: Why choose 120 volts?

[Owen DeLong]

On May 26, 2009, at 1:48 PM, Alex H. Ryu wrote:


Also, adding followings.

5) availability from local power provider(s)


I don't know of anywhere in the US/Canada where power comes into the
building as strictly 110-120V.  That is almost always delivered either  
as

1 leg of a 3-phase 208 service (most commercial/industrial deliveries)
or as two hots (240V across the two hots) and a neutral (120V from
either hot to neutral).  Most datacenters are taking much higher voltage
feeds from their utilities and most of the readily available step-down
transformers and UPSs will produce 208 three-phase or 240V as
described above.

I am not an expert on power outside of the US, but, to the best of my
knowledge, Japan's 100V/50Hz is one of the few other countries
using less than 208V as their standard.



6) local regulation such as fire department safety rules...


I seriously question this one.  Can you point to any examples?

7) for your own safety... (120V may not kill people, but 240V can  
do...)


It's relatively easy to kill someone with 12V, so, I don't see how 10x  
that
is significantly less dangerous than 20x.  Sticking your fingers in a  
light
socket is going to hurt regardless of the voltage.  Yes, 240V can hurt  
more
and faster, but, at the end of the day, it's not significantly more  
likely
to kill you than 110.  Fortunately, most servers don't have light  
sockets

in the high voltage portion of the server.



If you want better, why not just have everything to DC power ?
Something like 48V...


There's a whole host of reasons, but, the biggest one boils down
to cost... Cost of the larger wires, cost of the increased line losses,
etc.

Owen


Alex


Wayne E. Bouchard wrote:

1) Equipment used to not be dual voltage

2) For smaller scale, 120V UPS and distribution equipment is usually
cheaper

3) 120V embedded itself into operations as a result.

4) We're all lazy and hate change.

On Tue, May 26, 2009 at 12:39:10PM -0700, Seth Mattinen wrote:

I have a pure curiosity question for the NANOG crowd here. If you  
run

your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get  
away
with lower amperage circuits. I'm curious about the reasons for  
using

high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits.

~Seth



---
Wayne Bouchard
w...@typo.org
Network Dude
http://www.typo.org/~web/

Re: Why choose 120 volts?

[Janet Plato]

> Last time I looked at my bill I was being billed by the kWh, not amp and 240v 
>at half the amps is still the same wattage.

Losses are I^2*R, so double the voltage, half the current and
experience a quarter of the loss...

Janet Plato

Re: AH or ESP

[Nathan Ward]

On 27/05/2009, at 8:11 AM, Roland Dobbins wrote:



On May 27, 2009, at 3:00 AM, Tony Hain wrote:

Just because you can't use it for IPv4 is no reason to avoid using  
it for IPv6 now and let its momentum suppress the 66CGN walled  
garden mindset.


I concur quite strongly with your views on this particular topic,  
but the CGN boat appears to've sailed, AFAICT.



Note that Tony is talking about 6-to-6 NAT, not 6-to-4 NAT or vice  
versa (not to be confused with 6to4 tunnelling).


I'm not sure that boat has sailed yet.

--
Nathan Ward

Re: Why choose 120 volts?

[Barney Wolff]

Yes - think of all the nasty partial failure cases that can be eliminated -
each entire datacenter is either up or down.  Much simpler!

Getting back to reality, I've watched more than one electrician do a
two-finger liveness test on a 120v circuit, and done it myself.  240v
HURTS, and I've not seen a pro finger it deliberately.  But I haven't
actually asked.

On Tue, May 26, 2009 at 01:34:41PM -0700, Ray Sanders wrote:
> So when one server fails, all the rest fail too? 

> On Tue, 2009-05-26 at 16:29 -0400, Barney Wolff wrote:
> > Doesn't even need non-standard servers - just wire them all in series.
> > 
> > On Tue, May 26, 2009 at 03:23:46PM -0500, Kurt Anderson wrote:
> > > Why stop there? Grab a 20,000 volt feeder and create a Tesla datacenter.

-- 
Barney Wolff I never met a computer I didn't like.

Re: Why choose 120 volts?

[Leo Bicknell]

In a message written on Tue, May 26, 2009 at 12:39:10PM -0700, Seth Mattinen 
wrote:
> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?

If folks are making their own choices, mainly for historical and
convenience reasons.  If folks are building data centers for others,
it's that customers demand 120V power in many instances, for some
good, and many bad reasons.

However, for all the talk of power loss that's not the real issue.
The loss due to wire or amperage is a very small part of the equation.
While this paper is very much vendor produced, it's a good high
level summary none the less:

http://www.apcmedia.com/salestools/NRAN-6CN8PK_R0_EN.pdf

Note that in a 600Kw installation power loss is reduced from 8,894
W to 845 W, a savings of 1.3%.  Note that they have included the
savings from additional cooling in that figure.  Even at 1.3%, if
you looked at the cost of rewiring an existing data center based on
that figure you'd be nutty; return on investment would be forever.

But what you'll find in the paper is that the change allows you to
re-architect the power plant in a way that saves you money on PDU's,
transformers, and other stuff.  Thus this makes the most sense to
consider in a green field deployment.

Thus, to reframe your question, in your existing, already built out data
center is it worth replacing 120V circuits with 208V/230V ones to save
power?  No.  Savings is likely well under 1% in that situation, and time
you add in the capital cost to do the work it makes no sense.  In your
green field, new data center, does it make sense to look at power from an
entirely new point of view?  Quite possibly.

-- 
   Leo Bicknell - bickn...@ufp.org - CCIE 3440
PGP keys at http://www.ufp.org/~bicknell/


pgpSoHlvGJbAb.pgp
Description: PGP signature

Re: Why choose 120 volts?

[Seth Mattinen]

Joe Greco wrote:

208 isn't all that great.  On one hand, a 20A 208V circuit is vaguely
more convenient than a 30A 120V circuit because it is delivering a bit
more power to the rack (3328 vs 2880), and it's likely to work with a
lot of modern equipment containing autoranging power supplies.

>

On the flip side, with 120, you don't have to have "odd cords," and it
is somewhat easier to "right-size" power for a rack (20A, 30A, 2x20A),
so for an average rack that isn't crammed with high power webhosting
1U's (etc), a customer might actually find that the ability to right-
size the power feed is more flexible with 120V.


I don't find it makes much difference, really. People are used to 
working with 120 only because that's how we roll in the USA; scary high 
voltage is for the oven and dryer. I like odd cords; it makes the 
protected power stuff blazingly obvious and slightly harder to plug dumb 
things into a UPS branch circuit because hey, a plug is a plug, right?




And I don't like not having anywhere to plug in my power screwdriver's
recharger...  I suppose I should see if I can find someplace that has
a transformer of an appropriate size, or does anyone already have the
part number for something that can provide a few hunderd milliamps of
120V from 208?  :-)


True, you do lose the convenience outlet factor. I made up for it by 
placing standard 120V outlets (utility/generator only) along the walls. 
It works out because I hate those stupid "wall warts" with a passion. I 
go out of my way to buy products that come with a corded transformer, 
especially if it has a C14 connector on it.


If you're adept at electrical stuff you can always get a small 
transformer, put it in a box, stick a C14 on the high side and a 5-15 on 
the low side. Nothing fancy required.


~Seth

Re: Why choose 120 volts?

[Steve Bertrand]

Barney Wolff wrote:

> Getting back to reality, I've watched more than one electrician do a
> two-finger liveness test on a 120v circuit, and done it myself.  240v
> HURTS, and I've not seen a pro finger it deliberately.  But I haven't
> actually asked.

During my residential electrical apprenticeship, one of the tricks of
the trade I learnt was a quick two finger test on 120, but never
anything higher than that.

That was years ago. I would never do anything of the sort intentionally
ever again, even on low voltage systems (my girlfriend is an
Occupational Health and Safety Officer, and she frowns on that sort of
thing ;)

It really depends on your conductivity to ground ie what you are
standing on and the shoes you are wearing whether you will remain safe
by 'testing' for hotness on a circuit by touching it.

@120V, 1.2 mA is enough to tell you that the line is live. 15mA is the
let-go threshold, and 100mA can kill within a second. 200mA will pretty
much kill instantly.

Even at 120V on non-conductive ground, if you ever accidentally touched
the grounded box while touching the live wire, you will likely be dead
before the breaker trips.

Steve


smime.p7s
Description: S/MIME Cryptographic Signature

Re: Why choose 120 volts?

[Jared Mauch]

On May 26, 2009, at 4:23 PM, Kurt Anderson wrote:

Why stop there? Grab a 20,000 volt feeder and create a Tesla  
datacenter.

Think of all the copper you will save...



http://video.google.com/videoplay?docid=4468957986746104671

- Jared

Colo on the West Coast

[Pshem Kowalczyk]

Hi,

I'm looking for a colo provider somewhere on the west coast,
preferably somewhere close to one of the peering exchanges. A virtual
machine will do.
I want to use it to run a small performance monitoring box
(traceroutes, pings, etc). I also would like to get a full bgp feed
into it so I can monitor bgp as well.
Who do you think would be the best one to do it with?

(answers can be off-list)

kind regards
Pshem

RE: Why choose 120 volts?

[Dave Larter]

I stop at licking the 9v batteries, intentionally, but I have been
burned by 50KV before.  Just imagine the copper you could save by just
sending the energy thru the air, but then I guess the DC would sound and
look more like the death star.

-Original Message-
From: Jared Mauch [mailto:ja...@puck.nether.net] 
Sent: Tuesday, May 26, 2009 6:56 PM
To: Kurt Anderson
Cc: nanog@nanog.org
Subject: Re: Why choose 120 volts? 


On May 26, 2009, at 4:23 PM, Kurt Anderson wrote:

> Why stop there? Grab a 20,000 volt feeder and create a Tesla  
> datacenter.
> Think of all the copper you will save...
>

http://video.google.com/videoplay?docid=4468957986746104671

- Jared

Re: Why choose 120 volts?

[Matthew Moyle-Croft]

Jay Hennigan wrote:



Most of the rest of the world has 240v as conventional domestic power, 
and most server rooms or datacenters supporting >2KVA single devices 
have 208 or 240v available, so it makes sense for manufacturers of 
high-power gear to save the money on copper and connectors and insist 
on higher input voltages for full spec output.
We're all 230vac here in Oz (it's a compromise between our old 240v 
standard and the Euro 220v one).  In Oz we basically have a single style 
of outlet for AC for low amps and a couple of ones for higher amps.


The higher powered PSUs are much easier to deal with on that - everytime 
we get ready to commission a new router etc for the US or Japan we look 
in amazement at the endless list of NEMA plugs and voltage options and 
different kinds of APC power gear we need to do everything.   It kind of 
freaks me out - locking, not locking etc.  Admittedly I find the 
standard 2 pin US style power connector somewhat wobbly and scary - ours 
seems to lock in much better.  

Since we get the same gear as North America mostly almost all of it 
copes with 90v to 240v AC 50/60hz.   It's rare these days to find things 
without switching PSUs.  

It's worth noting that despite higher voltages here there aren't more 
deaths or injuries - but maybe it's because people take it more 
seriously.  Admittedly no one I know is nuts enough to use body parts 
for "liveness testing".


MMC







Yes, it would be nice to be able to plug in your laptop charger, etc. 
And the voltage on that charger is likely compatible with anything 
from 100 to 240V.  Wiring a NEMA 5-15 with 208V is just wrong, 
though.  I have an IEC male to NEMA 5-15 female pigtail (old-school 
"monitor cord") with a big sticker saying "208V - Be very careful what 
you plug in here" for just that purpose.


--
Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net
Impulse Internet Service  -  http://www.impulse.net/
Your local telephone and internet company - 805 884-6323 - WB6RDV

RE: Colo on the West Coast

[Ray Sanders]

Pshem,

Datapipe and hurricane electric come to mind.



Mobile email powered by the force...

 Original Message 
From: "Pshem Kowalczyk" 
Date: 5/26/09 4:03 pm
To: "nanog@nanog.org" 
Subj: Colo on the West Coast
Hi,

I'm looking for a colo provider somewhere on the west coast,
preferably somewhere close to one of the peering exchanges. A virtual
machine will do.
I want to use it to run a small performance monitoring box
(traceroutes, pings, etc). I also would like to get a full bgp feed
into it so I can monitor bgp as well.
Who do you think would be the best one to do it with?

(answers can be off-list)

kind regards
Pshem

Re: Why choose 120 volts?

[Chuck Anderson]

On Tue, May 26, 2009 at 03:39:30PM -0500, Joe Greco wrote:
> And I don't like not having anywhere to plug in my power screwdriver's
> recharger...  I suppose I should see if I can find someplace that has
> a transformer of an appropriate size, or does anyone already have the
> part number for something that can provide a few hunderd milliamps of
> 120V from 208?  :-)

We always seem to have an odd device or three that needs 120V, like a 
wallwart for an external modem or LCD KVM console, or some legacy 
specialized gear (CBORD comes to mind).  For those we have been 
providing a single circuit/PDU in the room that runs at 120V and 
running extension cords as necessary.  Everything else is 208V.

Re: AH or ESP

[Jack Kohn]

>
>
> The delusion that network operators can successfully use unhelpful
> protocols and/or smoke and mirrors to force idealist network design on
> others needs to end.  People use new protocols because they are better.
> If  the benefit of moving to a new protocol does not outweigh the pain
> of moving to it, people don't use it.  That's why the OSI protocols did
> not kill IP like they were supposed to in the 90s, it is why the largely
> forgotten mandated move from Windows to secure OSes (ie, Unix) for all
> government employees never happened, and it is why IPv6 is sputtering.
> If people want to use NAT, they are going to use NAT.  They may stop
> using it if the widespread adoption of peer to peer protocols means they
> are missing out on things other people are doing.  They are not going to
> stop using NAT to use a protocol maliciously designed to break it; they
> will just wait, patiently and nearly always successfully, for somebody
> to come out with a version that has no such malice.  They are certainly
> not going to stop using NAT because somebody tells them they should use
> a security protocol that does not secure anything worth securing.
>
> BitTorrent is a better anti-NAT tool than AH ever will be.  More carrot,
> less stick.
>

I agree. Folks are going to use ESP-NULL if they really want Integrity
Protection ..


> -Dave
>
>

Re: MX Record Theories

[Mark Andrews]

In message <163001.1243364...@turing-police.cc.vt.edu>, valdis.kletni...@vt.edu
 writes:
> --==_Exmh_1243364471_3846P
> Content-Type: text/plain; charset=us-ascii
> 
> On Tue, 26 May 2009 11:03:59 PDT, gb10hkzo-na...@yahoo.co.uk said:
> > would be most interested to hear NANOG theories on the variety of MX
> > record practices out there, namely, how come there seem to be so many
> > ways employed to achieve the same goal ?
> 
> The trick here is that it isn't always *exactly* "the same goal".  There's
> multiple mail system architectures and design philosophies.
> 
> One often overlooked but very important design point for the *large* provider
> s:
> 
> % dig aol.com mx
> ;; ANSWER SECTION:
> aol.com.2805IN  MX  15 mailin-01.mx.aol.com.
> aol.com.2805IN  MX  15 mailin-02.mx.aol.com.
> ...
> ;; WHEN: Tue May 26 14:40:41 2009
> ;; MSG SIZE  rcvd: 507
> 
> That 507 is critically important if you want to receive e-mail from sites
> with fascist firewalls that block EDNS0 and/or TCP/53.  5 bytes left. ;)

Actually TCP/53 out is almost always allowed.  Too many
things break if you block TCP/53 out.  Similarly TCP to
recursive servers is almost always allowed because blocking
it breaks too many things.

Recursive nameservers generally deal with stupid firewalls
by adjusting how they make their queries.

ed...@4096 -> ed...@512 -> plain DNS.

Stub resolvers generally don't do EDNS so the are not
impacted by stupid firewalls.  This will changes as DNSSEC
processing moves into the application.

A EDNS referral from the root servers to the COM servers
already exceeded 512 bytes.  The world hasn't fallen over.

That's dealt with that myth.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: mark_andr...@isc.org

Re: Why choose 120 volts?

[Chris Adams]

Once upon a time, Joe Greco  said:
> And I don't like not having anywhere to plug in my power screwdriver's
> recharger...  I suppose I should see if I can find someplace that has
> a transformer of an appropriate size, or does anyone already have the
> part number for something that can provide a few hunderd milliamps of
> 120V from 208?  :-)

Isn't 208V usually provided as a connection across two phases of a 3
phase circuit?  In that case, you get 120V by going between one phase
and neutral (no transformer required).

You need a NEMA 14 (4 wire) connector to get two phases, neutral, and
ground (provides 1 208V circuit and/or 2 120V circuits) or a NEMA L21
(5 wire) connector to get all three phases, neutral, and ground
(provides 3 208V circuits and/or 3 120V circuits).

-- 
Chris Adams 
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

RE: Why choose 120 volts?

[Dave Larter]

Yes, you are correct Chris.  The loss from getting 240 from two legs is
due to the fact that it is at 120 instead of 180 deg's.

-Original Message-
From: Chris Adams [mailto:cmad...@hiwaay.net] 
Sent: Tuesday, May 26, 2009 7:52 PM
To: Joe Greco
Cc: nanog@nanog.org
Subject: Re: Why choose 120 volts?

Once upon a time, Joe Greco  said:
> And I don't like not having anywhere to plug in my power screwdriver's
> recharger...  I suppose I should see if I can find someplace that has
> a transformer of an appropriate size, or does anyone already have the
> part number for something that can provide a few hunderd milliamps of
> 120V from 208?  :-)

Isn't 208V usually provided as a connection across two phases of a 3
phase circuit?  In that case, you get 120V by going between one phase
and neutral (no transformer required).

You need a NEMA 14 (4 wire) connector to get two phases, neutral, and
ground (provides 1 208V circuit and/or 2 120V circuits) or a NEMA L21
(5 wire) connector to get all three phases, neutral, and ground
(provides 3 208V circuits and/or 3 120V circuits).

-- 
Chris Adams 
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

Re: Why choose 120 volts?

[Joe Greco]

> Once upon a time, Joe Greco  said:
> > And I don't like not having anywhere to plug in my power screwdriver's
> > recharger...  I suppose I should see if I can find someplace that has
> > a transformer of an appropriate size, or does anyone already have the
> > part number for something that can provide a few hunderd milliamps of
> > 120V from 208?  :-)
> 
> Isn't 208V usually provided as a connection across two phases of a 3
> phase circuit?  In that case, you get 120V by going between one phase
> and neutral (no transformer required).

Yes, but this doesn't imply that you have access to those other phases.
It is easy enough to be delivered 208V single phase service in a data
center environment.

... 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.

Re: AH or ESP

[Merike Kaeo]

I agree as well that ESP-Null the way to go for integrity.  From  
operational perspective if you are supporting both v4 and v6 (and you  
will) then having different protocols will be a nightmare.  Common  
denominator is ESP-Null.


Realistically for IPsec, unless you have the scalable credential  
issue resolved and easier configs from vendors, the operational time  
sync will have many looking elsewhere to accomplish what's needed in  
the name of security. (total bummer IMHO).


- merike

On May 26, 2009, at 4:35 PM, Jack Kohn wrote:




The delusion that network operators can successfully use unhelpful
protocols and/or smoke and mirrors to force idealist network  
design on
others needs to end.  People use new protocols because they are  
better.
If  the benefit of moving to a new protocol does not outweigh the  
pain
of moving to it, people don't use it.  That's why the OSI  
protocols did
not kill IP like they were supposed to in the 90s, it is why the  
largely
forgotten mandated move from Windows to secure OSes (ie, Unix) for  
all
government employees never happened, and it is why IPv6 is  
sputtering.

If people want to use NAT, they are going to use NAT.  They may stop
using it if the widespread adoption of peer to peer protocols  
means they
are missing out on things other people are doing.  They are not  
going to
stop using NAT to use a protocol maliciously designed to break it;  
they
will just wait, patiently and nearly always successfully, for  
somebody
to come out with a version that has no such malice.  They are  
certainly
not going to stop using NAT because somebody tells them they  
should use

a security protocol that does not secure anything worth securing.

BitTorrent is a better anti-NAT tool than AH ever will be.  More  
carrot,

less stick.



I agree. Folks are going to use ESP-NULL if they really want Integrity
Protection ..



-Dave

RE: Why choose 120 volts?

[Dave Larter]

See:

http://www.3phasepower.org/3phasewiring.htm

-Original Message-
From: Joe Greco [mailto:jgr...@ns.sol.net] 
Sent: Tuesday, May 26, 2009 8:20 PM
To: Chris Adams
Cc: nanog@nanog.org
Subject: Re: Why choose 120 volts?

> Once upon a time, Joe Greco  said:
> > And I don't like not having anywhere to plug in my power
screwdriver's
> > recharger...  I suppose I should see if I can find someplace that
has
> > a transformer of an appropriate size, or does anyone already have
the
> > part number for something that can provide a few hunderd milliamps
of
> > 120V from 208?  :-)
> 
> Isn't 208V usually provided as a connection across two phases of a 3
> phase circuit?  In that case, you get 120V by going between one phase
> and neutral (no transformer required).

Yes, but this doesn't imply that you have access to those other phases.
It is easy enough to be delivered 208V single phase service in a data
center environment.

... 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.

Re: Why choose 120 volts?

[Paul Vixie]

Leo Bicknell  writes:

>...
> http://www.apcmedia.com/salestools/NRAN-6CN8PK_R0_EN.pdf
>...
> But what you'll find in the paper is that the change allows you to
> re-architect the power plant in a way that saves you money on PDU's,
> transformers, and other stuff.  Thus this makes the most sense to
> consider in a green field deployment.

noting also that "architect" is a noun, i find that on large plants the
cost of copper wire and circuit breakers add up, where sizes (and prices)
are based on ampherage not wattage.  in the old days when a rack needed
6kW, that was 208V 30A (10 gauge wire) or it was two of 120V 30A (also 10
gauge wire).  somewhere near the first hundred or so racks, the price of
the wire and breakers starts to seem high, and very much worth halving.

once in a while some crashcart CRT monitor won't run on anything but 120V
but for $50 NRC it can be replaced with an LCD.  everything else that's
still worth plugging in (that is, having a power/heat cost per performance
better than that of a blow dryer) doesn't care what voltage it lives on.
-- 
Paul Vixie
KI6YSY

Re: Colo on the West Coast

[Paul Vixie]

Pshem Kowalczyk  writes:

> (answers can be off-list)

See .  (updates still welcomed, btw.)
-- 
Paul Vixie
KI6YSY

Re: Why choose 120 volts?

[Ricky Beam]

On Tue, 26 May 2009 19:51:42 -0400, Chris Adams  wrote:

Isn't 208V usually provided as a connection across two phases of a 3
phase circuit?  In that case, you get 120V by going between one phase
and neutral (no transformer required).


Indeed it is.  If you want to see it yourself, measure the voltage between  
"hots" on different circuits.  I see 208-212V depending on the legs (they  
aren't evenly loaded.)  This is easier to do in a data center, but with a  
long extention cord it can be done with the office. :-) (of course, having  
the building wiring diagram(s) makes for a short hunt.)


--Ricky

Re: Why choose 120 volts?

[Ricky Beam]

On Tue, 26 May 2009 20:32:54 -0400, Paul Vixie  wrote:

once in a while some crashcart CRT monitor won't run on anything but 120V
but for $50 NRC it can be replaced with an LCD.  everything else that's
still worth plugging in (that is, having a power/heat cost per  
performance better than that of a blow dryer) doesn't care what voltage

it lives on.


Or go to Radio Shack and get one of those "international traveler" power  
converter packs.


I have a number of systems (ok, yes, they're old) that a) do not have  
autosensing power supplies (someone has to get a paperclip and flip a  
switch), and b) will not work on 208v -- 120 or 240, but not 208.


--Ricky

Re: Why choose 120 volts?

[Ulf Zimmermann]

On Tue, May 26, 2009 at 12:39:10PM -0700, Seth Mattinen wrote:
> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?
> 
> I've been running my facility at 208 for years because I can get away
> with lower amperage circuits. I'm curious about the reasons for using
> high-amp 120 volt circuits to drive racks of equipment instead of
> low-amp 208 or 240 volt circuits.
> 
> ~Seth

I love 208V but I have to fight almost everytime with our datacenter
provider. They got 50 or so "Colo's" which are all cookie cutter. Then
there is our datacenter, the only facility where they can deliver
3-phase and monitor actual power usage. Everytime when we ask for 3-phase
it is a fight now. Our latest circuits (50-amp although we won't use more
than 16A under normal use (A+B load)), took me 9 months to get out of
them. :-(

-- 
Regards, Ulf.

-
Ulf Zimmermann, 1525 Pacific Ave., Alameda, CA-94501, #: 510-865-0204
You can find my resume at: http://www.Alameda.net/~ulf/resume.html

Re: Why choose 120 volts?

[Seth Mattinen]

Joe Greco wrote:
>> Once upon a time, Joe Greco  said:
>>> And I don't like not having anywhere to plug in my power screwdriver's
>>> recharger...  I suppose I should see if I can find someplace that has
>>> a transformer of an appropriate size, or does anyone already have the
>>> part number for something that can provide a few hunderd milliamps of
>>> 120V from 208?  :-)
>> Isn't 208V usually provided as a connection across two phases of a 3
>> phase circuit?  In that case, you get 120V by going between one phase
>> and neutral (no transformer required).
> 
> Yes, but this doesn't imply that you have access to those other phases.
> It is easy enough to be delivered 208V single phase service in a data
> center environment.
> 
> ... JG

Correct. I have a Smart-UPS RT connected across two legs of 3 phase for
208. The unit does not have a neutral, only ground, so it's 3 wires in
and 3 out. The output is only 208 L-L with odd voltages on L-G. Since
there's no neutral, it can only be used to drive 208 loads or a
transformer for 120.

~Seth

Re: The adventures of Team ARIN

[Jeffrey Lyon]

At least now we know where all those fees end up.

Jeff

On Tue, May 26, 2009 at 11:14 AM, Jeroen Massar  wrote:
> Semi-Off-Topic here, I know, but it might help Network Operators to
> explain certain misguided people and thus lower noise and raise signal
> in various places.
>
> https://www.arin.net/knowledge/comic.html
>
> Short short synopsis: comic about how ARIN handles certain things and
> what ARIN does etc.
>
> Greets,
>  Jeroen
>
> --
> Currently published issues:
>
> Issue 1 - The Beginning of Team ARIN
> -
> Synopsis: In issue 1, learn how Team ARIN was founded with the
> assistance of Jon Postel. See how active participation by the entire
> Internet community is key to Team ARIN's  success as it endeavors to
> facilitate the open and transparent, bottom-up policy development processes.
>
> Issue 2 - "FUD for Thought"
> -
> Synopsis: In issue 2, Team ARIN embarks on a mission to raise awareness
> about the issue of depletion of the available pool of IPv4 addresses and
> encounters a new enemy -- Agent FUD. Working for the "Bad Idea Force,"
> FUD is busy trying to spread fear, uncertainty, and doubt about IPv4
> address depletion. Using newly acquired technology, Team ARIN combines
> forces to help combat this new enemy of the open and transparent
> principles the Internet is based on, and in doing so creates something
> more than even they expected!
>
> Issue 3 - "FUD 2.0 - Return of the FUD Factor!"
> -
> Synposis: Issue 3 begins with Team ARIN flying back from a conference
> when they are alerted to a new problem and an old enemy. Agent FUD has
> returned and this time he's seeking to undermine the Internet
> community's migration to IPv6. Read the issue to find out how Team ARIN
> saves the day and how you can help!
>
>
> (s/synposis/synopsis/ by me, that typo is still on the original site,
> rest of content all by ARIN, nothing I can do about, thus don't complain
> to me ;)
>
>
>



-- 
Jeffrey Lyon, Leadership Team
jeffrey.l...@blacklotus.net | http://www.blacklotus.net
Black Lotus Communications of The IRC Company, Inc.

Look for us at HostingCon 2009 in Washington, DC on August 10th - 12th
at Booth #401.

Re: Why choose 120 volts?

[david raistrick]

On Tue, 26 May 2009, Joe Greco wrote:


Once upon a time, Joe Greco  said:

And I don't like not having anywhere to plug in my power screwdriver's
recharger...  I suppose I should see if I can find someplace that has



Yes, but this doesn't imply that you have access to those other phases.
It is easy enough to be delivered 208V single phase service in a data
center environment.



Uh.  208v single phase is functionally the same as 240v single phase. 
You grab 1 hot, neutral off the ground, and you have a common 110v 
circuit.  Even if you're 3 phase to your PDU, it's still single phase to 
the servers. (specialty gear excluded, but those generally plug direct to 
the circuit, not to a PDU).


This makes it very very easy to solve this problem, and I keep a few of 
these floating around at all of my datacenters, with big labels saying who 
they belong too.  (ignoring the fact that for drill charging at least 
there's usually house power available, but crash carts need these...)



C14 (M) to 5-15 (F) adaptor cable:

http://www.cdw.com/shop/products/default.aspx?edc=1036852

I also use them to run wall warts, etc, as needed.



---
david raistrickhttp://www.netmeister.org/news/learn2quote.html
dr...@icantclick.org http://www.expita.com/nomime.html

Re: Why choose 120 volts?

[Luke S Crawford]

Seth Mattinen  writes:

> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?

I've spent the last several days going back and forth with salespeople,
trying to find a rack with 208v power in the south bay, or a cheap 100M
connection from market post tower to heraklesdata in Sacramento.  (where
I have cheap 208v power)   From what I see, most places in the bay area 
just can't handle the kind of heat density that a 30a 208v circuit per rack 
would bring.  (they won't sell me more than 2 20A 120v circuits, either, and 
many will only sell me a single 15a circuit per rack.  I assume that's an 
effort to keep the heat output within cooling system capabilities.)  But 
that still doesn't explain why they don't hand out 10a  208v circuits.  

I've also seen employers pick 208v over 120v even after I pointed out
the cost per watt advantages of 208v, even without counting efficiency 
gains.  In one case they provisioned one rack with 208v, because the 
vendor of some particularly expensive bit of equipment recommended it, 
then they left all the commodity servers on 120v.  Why didn't they put 
everything on 208v?   I pointed out that the cost per watt was lower.
Maybe I blew my credibility by wanting to research 48v power supplies for
our kit before that?  (it was a telco facility, after all, and I was
young.)  

30a 208v is about perfect for a rack, if you ask me.  (I imagine
the guys who have to deal with cooling feel differently, but at my
scale, that's all priced into the power.)  

-- 
Luke S. Crawford
http://prgmr.com/xen/  -   Hosting for the technically adept
   We don't assume you are stupid.  

Re: The adventures of Team ARIN

[Randy Bush]

> https://www.arin.net/knowledge/comic.html
> 
> Short short synopsis: comic about how ARIN handles certain things and
> what ARIN does etc.

imiho, an embarrassment to arin and to the internet

randy

Re: Why choose 120 volts?

[Joe Greco]

> On Tue, 26 May 2009, Joe Greco wrote:
> >> Once upon a time, Joe Greco  said:
> >>> And I don't like not having anywhere to plug in my power screwdriver's
> >>> recharger...  I suppose I should see if I can find someplace that has
> 
> > Yes, but this doesn't imply that you have access to those other phases.
> > It is easy enough to be delivered 208V single phase service in a data
> > center environment.
> 
> Uh.  208v single phase is functionally the same as 240v single phase. 

Yes, functionally, it is.

> You grab 1 hot, neutral off the ground, and you have a common 110v 
> circuit.  Even if you're 3 phase to your PDU, it's still single phase to 
> the servers. (specialty gear excluded, but those generally plug direct to 
> the circuit, not to a PDU).

Go tell your electrical inspector that you're using the ground as a 
neutral.  I'll make the popcorn ...  put simply, that's not allowed,
for Very Good Reasons.

> This makes it very very easy to solve this problem, 

No it doesn't, and the following doesn't even seem to relate:

> and I keep a few of 
> these floating around at all of my datacenters, with big labels saying who 
> they belong too.  (ignoring the fact that for drill charging at least 
> there's usually house power available, but crash carts need these...)
> 
> C14 (M) to 5-15 (F) adaptor cable:
> 
> http://www.cdw.com/shop/products/default.aspx?edc=1036852
> 
> I also use them to run wall warts, etc, as needed.

Great, you're the latest person to invent a way to present a 5-15R that
offers something besides 120VAC.  This is neither new nor novel, but it
*is* dangerous and risky, and in no way "solves the problem."

Plugging a device that is designed to run on 120V into 208V will probably 
result in (at least!) one of:

1) smoke

2) fire

3) burning components

4) dead device

5) burning batteries (in the case of the aforementioned charger)

6) general excitement and panic in the data center in the event that 
   none of the above happen immediately, but rather some time after
   you leave.

7) etc.

The basic problem here is that there are still many devices out there 
that do not have autoranging power supplies.

As for "for drill charging at least there's usually house power available",
well, that sucks.  We're at Equinix.  There are periods where no one uses
the drill, or the power screwdriver, for months at a time.  With 120V in
the cage, I left the chargers hooked up and trickle charging.  Neither the
drill nor the power screwdriver have autoranging power supplies.  So now
with 208V, someone has to bring along batteries, because we can't leave
them on-site, or they'll go stale.  Bleh.

... 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.

Re: Checking bogon status of new address space

[Oliver Hookins]

Thanks for all your suggestions on this topic. For what it's worth, I
attempted a few of the suggestions as well as my own idea and documented the
outcomes here:

http://www.anchor.com.au/blog/2009/05/testing-your-connectivity/

In summary, there's no definitive method for testing your connectivity is
perfect (obviously) but I was able to determine (hopefully with reasonable
accuracy) that there are a significant amount of ASs out there not reachable
from our new address space, at least by IPv4 ICMP.

-- 
Regards,
Oliver Hookins
Anchor Systems

Out of warranty APC PDU repair

[Oliver Hookins]

Hi all, hopefully this isn't too off topic (since it's datacentre related).

We have an APC AP7952 rack PDU which has stopped working. I believe the
management module is faulty, and it is about 5 years old. APC don't service
these outside of warranty at all so I'm trying to find a 3rd-party repairer.
So far APC doesn't seem to understand this concept.

Can anyone suggest a company that would work on these units in Sydney,
Australia or nearby?

-- 
Regards,
Oliver Hookins
Anchor Systems

Re: The adventures of Team ARIN

[Kevin Oberman]

> Date: Wed, 27 May 2009 13:19:55 +0900
> From: Randy Bush 
> 
> > https://www.arin.net/knowledge/comic.html
> > 
> > Short short synopsis: comic about how ARIN handles certain things and
> > what ARIN does etc.
> 
> imiho, an embarrassment to arin and to the internet

Initially I thought the same thing, but the feedback from the large
number of totally clueless ARIN "customers" has been overwhelmingly
positive. 

Clearly, the comic book was never intended for the typical subscriber to
this list.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: ober...@es.net  Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751

Re: Why choose 120 volts?

[Barton F Bruce]

Seth Mattinen wrote: 
I have a pure curiosity question for the NANOG crowd here. If you run
your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get away
with lower amperage circuits. I'm curious about the reasons for using
high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits
And you have been doing something that is a right step in the right direction, 
but may well not be the best ultimate solution.

Lets half ignore codes. Not to be illegal, but they CAN be changed and you can 
often get specific exceptions if you are not just in the back room of an office 
but are in a clearly professionally managed facility with well trained staff 
plugging in equipment.

Every time I look at a nameplate and I see 100-250VAC I get very frustrated. If 
only that had been perhaps 100-300VAC, I could then run it on 277VAC and that 
is especailly nice for many reasons.

Most large USA buildings already have 277 and probably all their flourescent 
lighting is run off it (277VAC ballasts are readily available and what look 
like rats-ass wall switches but are higher rated ones are readily available - 
both even at home despot if you look hard enough), so nothing terribly new has 
to be learned by electricians, etc.

277 is the phase leg to NEUTRAL voltage of a 277/480 WYE system that most 
everything except small human plugged appliances use in any but the very 
largest USA  office building. It is what typically comes in from the power 
company.

120/208 is the output of typically a delta/wye transformer that steps that down 
for the dumb humans to safely use and you are paying the penalty of the WHOLE 
LOAD having to go through a second less than 100% efficient transformer.

The beauty of 277 is that on a single breaker pole (unlike 208 where you are 
most likely to have 2 HOT legs and need a 2 pole simultaneous trip breaker) on 
reasonable size branch circuits that you are still allowed to plug MULTIPLE 
loads into without individual fuses or breakers (that is "allowed to" - you may 
chose to protect each outlet in the rack, but that is not compulsory) you get 
277/120=2.31 times as much power available.

Sadly routers, servers, switches, etc. typically are rated to 250VAC, so using 
raw 277 won't work. But let us see how close HP/IBM/ACP and many many others 
are getting still using ONE breaker pole per much more efficient branch 
circuit. NB that as you go to larger branch circuits in AMPS, you MUST be 
supplying just ONE load or MUST have additioanl breakers or fuses  as you split 
it up. 

We all know 120/208 and 277/480. What about another NEW pair of voltages in WYE 
connection! Lets use 240/415. It is exactly twice 120/208 (well it is not 
stated as 240/416  I'd guess since 240 x 1.73259 = 415.82  they just truncate 
rather than round - though 2400/4160 is a standard designation...) and is 
inside the 250V max rating of the switching power supplies. It still uses a 
single breaker pole. Your get EXACTLY twice as much power out of a 240/415 WYE 
branch circuit as you would out of a 120/208 at the same AMPs. But you may save 
a transformer and its continuous power waste or at least part of it in between. 

How do you get to 240/415 is the next issue. If you have 2400/4160 or 
7,960/13,800 primary into your building, and you do all your own transformers, 
getting 240/415(6) can be a single transformer step for you, and you will  
probably have many transformers so can also create seperate 277/480 for modest 
size AC inits and lighting, While LARGE chillers can be ordered at the higher 
voltages, and for the relatively small amount of 120/208 you probably should 
come off 277/480 into standard 120/208 delta wye transformers because normal 
electricians can do that rather then the 13K gods().

But if you are a smaller building the only voltage that makes sense that the 
utility is supporting is 277/480. Rather than take all your rack power through 
another transformer step with the losses and the extra heat to eject from the 
building, consider instead using buck (as in the classic BOOST/BUCK 
transformers)  to knock that 277/480 down to 240/415.  It can be packaged as a 
3 phase unit  for less than three singles, and will be smaller and less costly 
to have wired up, but the three singles may be available from stock. 

It is the same sort of device you must have in front of a load that needs 240 
or 250 and can't handle 208, but in that case is wired BOOSTING rather than 
BUCKING.  FWIW an electric range burner or a hot water heater element rated for 
240 produces EXACTLY 75% of the heat if run on 208 (go do the math...), but you 
should NOT use boost bucks for such a simple situation because optional heating 
elements can be ordered originally OR bought as replacements for less than $10 
each and easily replaced in the field to give the original 240 rated wattage on 
208 supply.

In any case the 3 phase b

Re: Out of warranty APC PDU repair

[Joel Jaeggli]

Oliver Hookins wrote:
> Hi all, hopefully this isn't too off topic (since it's datacentre related).
> 
> We have an APC AP7952 rack PDU which has stopped working. I believe the
> management module is faulty, and it is about 5 years old. APC don't service
> these outside of warranty at all so I'm trying to find a 3rd-party repairer.
> So far APC doesn't seem to understand this concept.

The mangement module is a tiny 486 equivalent embedded linux box, I'm
not sure there's actually much to repair in there.

> Can anyone suggest a company that would work on these units in Sydney,
> Australia or nearby?
> 

Re: AH or ESP

[Randy Bush]

> IPsec as a whole is compliance mandatory for IPv6 although for new  
> version of IPv6 Node requirements that came out recently I think they  
> changed that to a 'SHOULD'.

the reality is DON'T

Re: Multi-homed clients and BGP timers

[Steve Bertrand]

Steve Bertrand wrote:

> My problem is the noticeable delay for switchover when the fibre happens
> to go down (God forbid).
> 
> I would like to know if BGP timer adjustment is the way to adjust this,
> or if there is a better/different way. It's fair to say that the fibre
> doesn't 'flap'. Based on operational experience, if there is a problem
> with the fibre network, it's down for the count.

Thanks to all for the great feedback. In summary, I've learnt:

- Even though BFD would be a fantastic solution and would require only
minimal changes (to my strict uRPF setup), it's a non-starter, as I
don't fit all of the requirements that Ivan pointed out

- fast-external-fallover is already enabled by default, but in order for
this to be effective, the interface has to physically go into down
state. In my case, although not impossible, it is extremely unlikely

- adjusting BGP timers is the best option given it's really the only one
left. Although I generally try to keep consistency among all equipment
(if I set the timers at one end, I would set them the same at the
other). Iljitsch recommended to leave the CPE end alone, so if something
bad happens, access to the CPE would not be necessary to revert the change

- I'm going to set the timers to 5/16. I like the idea of the extra
second on top of being divisible by three. That will ensure that at
least three keepalives have a chance to make it before the session hold
timer is reached

Cheers!

Steve



smime.p7s
Description: S/MIME Cryptographic Signature

The adventures of Team ARIN

[Jeroen Massar]

Semi-Off-Topic here, I know, but it might help Network Operators to
explain certain misguided people and thus lower noise and raise signal
in various places.

https://www.arin.net/knowledge/comic.html

Short short synopsis: comic about how ARIN handles certain things and
what ARIN does etc.

Greets,
 Jeroen

--
Currently published issues:

Issue 1 - The Beginning of Team ARIN
-
Synopsis: In issue 1, learn how Team ARIN was founded with the
assistance of Jon Postel. See how active participation by the entire
Internet community is key to Team ARIN's  success as it endeavors to
facilitate the open and transparent, bottom-up policy development processes.

Issue 2 - "FUD for Thought"
-
Synopsis: In issue 2, Team ARIN embarks on a mission to raise awareness
about the issue of depletion of the available pool of IPv4 addresses and
encounters a new enemy -- Agent FUD. Working for the "Bad Idea Force,"
FUD is busy trying to spread fear, uncertainty, and doubt about IPv4
address depletion. Using newly acquired technology, Team ARIN combines
forces to help combat this new enemy of the open and transparent
principles the Internet is based on, and in doing so creates something
more than even they expected!

Issue 3 - "FUD 2.0 - Return of the FUD Factor!"
-
Synposis: Issue 3 begins with Team ARIN flying back from a conference
when they are alerted to a new problem and an old enemy. Agent FUD has
returned and this time he's seeking to undermine the Internet
community's migration to IPv6. Read the issue to find out how Team ARIN
saves the day and how you can help!


(s/synposis/synopsis/ by me, that typo is still on the original site,
rest of content all by ARIN, nothing I can do about, thus don't complain
to me ;)




signature.asc
Description: OpenPGP digital signature

[NANOG-announce] NANOG46 reminders

[Betty Burke]

Hi Folks:

One Last set of meeting reminders!!

If you have not yet made your hotel reservations, you might want to consider 
doing so as the NANOG hotel room rate ends on Friday, May 29.

Make sure to complete your NANOG registration soon, you do not want to miss out 
on an excellent program and opportunity to catch up in person with members of 
the NANOG community.  On Monday, June 8 the registration late fee goes into 
effect.

Lastly, do not forget to get those lighting talk ideas submitted!

Look forward to seeing everyone in sunny Philly.

Sincerely,

Merit, NANOG Support Team


___
NANOG-announce mailing list
nanog-annou...@nanog.org
http://mailman.nanog.org/mailman/listinfo/nanog-announce

OT: ARIN Information

[John Curran]

On May 26, 2009, at 11:14 AM, Jeroen Massar wrote:


Semi-Off-Topic here, I know, but it might help Network Operators to
explain certain misguided people and thus lower noise and raise signal
in various places.


Another resource is the recent slide deck released for community use:


People who have further need for education or information materials
for ARIN and IPv4/IPv6 address issues are encouraged to follow up on
the  mailing list.

Thanks!
/John

John Curran
Acting President and CEO
ARIN

MX Record Theories

[gb10hkzo-nanog]

Hello all,

First, I hope this is not off-topic for NANOG, please be gentle with me as this 
is my first post.

I
would be most interested to hear NANOG theories on the variety of MX
record practices out there, namely, how come there seem to be so many
ways employed to achieve the same goal ?  Do you have experience in
more than one of these methods and which do you favour ?

To illustrate my question :

(1)
If you query the MX records for, Hotmail or AOL you will receive 4
equal weight MX records, each of the MX records having a round-robin
set of IPs.
e.g.
hotmail.com.2706INMX5 mx4.hotmail.com.
hotmail.com.2706INMX5 mx1.hotmail.com.
hotmail.com.2706INMX5 mx2.hotmail.com.
hotmail.com.2706INMX5 mx3.hotmail.com.
-and-
mx3.hotmail.com.1926INA65.xxx
mx3.hotmail.com.1926INA65.xxx
mx3.hotmail.com.1926INA65.xxx
etc.etc.

(2)
Alternatively, some people, particularly the ones that use hosted
filtering, tend to have one MX record, which as multiple round robin
IPs.
e.g.
microsoft.com.780INMX10 mail.global.frontbridge.com.
-and-
mail.global.frontbridge.com. 1728 INA65.xxx
mail.global.frontbridge.com. 1728 INA207.xxx
etc. etc.

(3) And others simply have a more traditional setup using multiple MX records 
and only one IP per MX record with no round robin
apple.com.931INMX10 mail-in14.apple.com.
apple.com.931INMX20 mail-in3.apple.com.
apple.com.931INMX20 eg-mail-in2.apple.com.
etc.etc.


So
what's the big deal ?  Please note I'm not asking which is "better" ...
I am just curious and interested to hear your professional opinions and
experiences.

Personally, I favour the simple option 3, multiple MX records.

Thanks y'all.

Re: MX Record Theories

[Alex H. Ryu]

I don't think there is no real answer for your question.
It depends on each company's business objective, the cost, network
topology, and their policy.
MX record is the the mechanism for mail delivery procotol.
It doesn't dictate how to implement.
Depending on mail volume, and network policy, you can implement actual
mail servers within DNS/SMTP protocol.

There are multiple ways to get things done.
Depending on budget, business objective, network resource/policy,
you can choose the way that fits to your need.

It is same as Microsoft Windows operating system.
Microsoft release the Windows, but it doesn't say you have to run it as
cluster or not.
Depending on your need, and your own analysis/decision, you can run
whatever you like.


Alex


gb10hkzo-na...@yahoo.co.uk wrote:
> Hello all,
>
> First, I hope this is not off-topic for NANOG, please be gentle with me as 
> this is my first post.
>
> I
> would be most interested to hear NANOG theories on the variety of MX
> record practices out there, namely, how come there seem to be so many
> ways employed to achieve the same goal ?  Do you have experience in
> more than one of these methods and which do you favour ?
>
> To illustrate my question :
>
> (1)
> If you query the MX records for, Hotmail or AOL you will receive 4
> equal weight MX records, each of the MX records having a round-robin
> set of IPs.
> e.g.
> hotmail.com.2706INMX5 mx4.hotmail.com.
> hotmail.com.2706INMX5 mx1.hotmail.com.
> hotmail.com.2706INMX5 mx2.hotmail.com.
> hotmail.com.2706INMX5 mx3.hotmail.com.
> -and-
> mx3.hotmail.com.1926INA65.xxx
> mx3.hotmail.com.1926INA65.xxx
> mx3.hotmail.com.1926INA65.xxx
> etc.etc.
>
> (2)
> Alternatively, some people, particularly the ones that use hosted
> filtering, tend to have one MX record, which as multiple round robin
> IPs.
> e.g.
> microsoft.com.780INMX10 mail.global.frontbridge.com.
> -and-
> mail.global.frontbridge.com. 1728 INA65.xxx
> mail.global.frontbridge.com. 1728 INA207.xxx
> etc. etc.
>
> (3) And others simply have a more traditional setup using multiple MX records 
> and only one IP per MX record with no round robin
> apple.com.931INMX10 mail-in14.apple.com.
> apple.com.931INMX20 mail-in3.apple.com.
> apple.com.931INMX20 eg-mail-in2.apple.com.
> etc.etc.
>
>
> So
> what's the big deal ?  Please note I'm not asking which is "better" ...
> I am just curious and interested to hear your professional opinions and
> experiences.
>
> Personally, I favour the simple option 3, multiple MX records.
>
> Thanks y'all.
>
>
>   
>
>
>
>
>   

Re: MX Record Theories

[Valdis . Kletnieks]

On Tue, 26 May 2009 11:03:59 PDT, gb10hkzo-na...@yahoo.co.uk said:
> would be most interested to hear NANOG theories on the variety of MX
> record practices out there, namely, how come there seem to be so many
> ways employed to achieve the same goal ?

The trick here is that it isn't always *exactly* "the same goal".  There's
multiple mail system architectures and design philosophies.

One often overlooked but very important design point for the *large* providers:

% dig aol.com mx
;; ANSWER SECTION:
aol.com.2805IN  MX  15 mailin-01.mx.aol.com.
aol.com.2805IN  MX  15 mailin-02.mx.aol.com.
...
;; WHEN: Tue May 26 14:40:41 2009
;; MSG SIZE  rcvd: 507

That 507 is critically important if you want to receive e-mail from sites
with fascist firewalls that block EDNS0 and/or TCP/53.  5 bytes left. ;)



pgpVa3ctskTZ8.pgp
Description: PGP signature

Re: MX Record Theories

[William Herrin]

On Tue, May 26, 2009 at 2:03 PM,   wrote:
> I would be most interested to hear NANOG theories on the variety of MX
> record practices out there, namely, how come there seem to be so many
> ways employed to achieve the same goal ?  Do you have experience in
> more than one of these methods and which do you favour ?

> apple.com.931INMX10 mail-in14.apple.com.
> apple.com.931INMX20 mail-in3.apple.com.
> apple.com.931INMX20 eg-mail-in2.apple.com.
> etc.etc.

Use this when only the front server is fully capable of processing the
mail into the domain. The other servers will have to hold some or all
of the mail until the first server or its cold spare returns to
service. Or perhaps the secondary servers are fully capable but
undesirable for some other reason, such as slower hardware or older
versions of the software.

> microsoft.com.780INMX10 mail.global.frontbridge.com.
> -and-
> mail.global.frontbridge.com. 1728 INA65.xxx
> mail.global.frontbridge.com. 1728 INA207.xxx

Use this when you have multiple front-end servers any of which is
fully capable of handling all messages entering the system. Free load
balancer built into the protocol.


> hotmail.com.        2706    IN    MX    5 mx4.hotmail.com.
> hotmail.com.        2706    IN    MX    5 mx1.hotmail.com.
> hotmail.com.        2706    IN    MX    5 mx2.hotmail.com.
> hotmail.com.        2706    IN    MX    5 mx3.hotmail.com.
> -and-
> mx3.hotmail.com.    1926    IN    A    65.xxx
> mx3.hotmail.com.    1926    IN    A    65.xxx
> mx3.hotmail.com.    1926    IN    A    65.xxx

Use this when you have a large number of front-end servers fully
capable of handling messages entering the system -and- you're somewhat
clueful.

The difference is that you want the IP addresses of the servers to be
included as "additional" information in the DNS response. If you have
a large number of addresses, they're all under the same name and
including them all would make the DNS response packet larger than a
few hundred bytes, the server will drop the additional information,
requiring a second DNS lookup and possibly a third TCP-based DNS
lookup in order to get it. By splitting them up, the DNS server will
pack as many sets of addresses as it can into the original response
packet.

Regards,
Bill Herrin



-- 
William D. Herrin  her...@dirtside.com  b...@herrin.us
3005 Crane Dr. .. Web: 
Falls Church, VA 22042-3004

PLNOG3 - 10-11.09.2009 - Call for Papers!

[Lukasz Bromirski]

Hello,

Polish Network Operators Group (PLNOG)[1] will meet for the third
time ever on 10th and 11th of September 2009 in Cracow, Poland.

We would like to invite You all to submit your presentation proposal.

The plan for PLNOG 3rd is to have three tracks:

* Architectures and technologies - sessions covering networking
  solutions, future of standards and the standarization process
  for current technologies;

* Real-life deployments and best practices - sessions covering
  first-hand experience with deployment of specific solutions,
  products and solutions

* Content provider architecture and scalability - dedicated for
  people interested in building backends for all kinds of
  networking sites like portals, community sites and etc.

Additionally, we would like to invite You to suggest subjects for the
open discussion sessions that will take place before the main event
and after the keynotes. Last subjects revolved around IPv6 deployment
and lawful intercept issues from the government and practical point
of view.

The submissions will be discussed by the PLNOG board[2], so the dead
line for them is 25th of June, 2009. The full agenda with all
sessions will be published no later than to 10th of July, 2009.

CfP proposals should be sent to following e-mail:

 andrzej.targosz {%} proidea.org.pl

with the prefix 'PLNOG3' in subject.

We would also like to invite all vendors to participate in
presentations - however, bear in mind please no vendor-oriented
sessions will be permitted, which means no sales, no marketing, only
pure technical stuff. The pointers to some specific design issues,
products or solutions are allowed if they follow approved presentation
flow and are relevant to subject covered.

Last but not least - if You want to sponsor PLNOG we'd be more than
happy to discuss this with You.

[1]. http://www.plnog.pl
[2]. http://plnog.pl/komiter-i-rada-nog/lang-pref/en/

--
"Don't expect me to cry for all the |   Łukasz Bromirski
 reasons you had to die" -- Kurt Cobain |http://lukasz.bromirski.net

Why choose 120 volts?

[Seth Mattinen]

I have a pure curiosity question for the NANOG crowd here. If you run
your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get away
with lower amperage circuits. I'm curious about the reasons for using
high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits.

~Seth

RE: Why choose 120 volts?

[Alex Rubenstein]

> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?

Because we are stupid.


> I've been running my facility at 208 for years because I can get away
> with lower amperage circuits. I'm curious about the reasons for using
> high-amp 120 volt circuits to drive racks of equipment instead of
> low-amp 208 or 240 volt circuits.

That makes you smarter than the average guy.

But, if we were really smart, we'd run at least 277, or maybe 347. Countless 
amounts of money would be saved on losses (transformation), copper (smaller 
wire), and many other areas. Most of the stuff we all run is already insulated 
for these voltage levels.

Even better would be all two pole 2 pole 480's or 2 pole 600's, then we 
wouldn't need neutrals.

RE: AH or ESP

[Tony Hain]

Merike Kaeo wrote:
...
>   ESP-Null came about when folks
> realized AH could not traverse NATs.

Thus the absolute reason why people should promote AH to kill off the 66nat
nonsense. Just because you can't use it for IPv4 is no reason to avoid using
it for IPv6 now and let its momentum suppress the 66CGN walled garden
mindset. 

Tony

Re: Why choose 120 volts?

[Kevin Oberman]

> From: Alex Rubenstein 
> Date: Tue, 26 May 2009 15:43:20 -0400
> 
> > I have a pure curiosity question for the NANOG crowd here. If you run
> > your facility/datacenter/cage/rack on 120 volts, why?
> 
> Because we are stupid.
> 
> 
> > I've been running my facility at 208 for years because I can get away
> > with lower amperage circuits. I'm curious about the reasons for using
> > high-amp 120 volt circuits to drive racks of equipment instead of
> > low-amp 208 or 240 volt circuits.
> 
> That makes you smarter than the average guy.
> 
> But, if we were really smart, we'd run at least 277, or maybe
> 347. Countless amounts of money would be saved on losses
> (transformation), copper (smaller wire), and many other areas. Most of
> the stuff we all run is already insulated for these voltage levels.
> 
> Even better would be all two pole 2 pole 480's or 2 pole 600's, then
> we wouldn't need neutrals.

Oh, yeah! Nothing sounds like more fun than working in a room full of
480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
have a functioning heart.)
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: ober...@es.net  Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751