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On 18/01/2012 03:04 AM, Darren New wrote:
> Google has hundreds of computers in their data centers. Unfortunately
> for you, Google counts "a shipping container full of thousands of mother
> boards and disk drives" as "a computer". ;-) It's really quite awesome.
> Upgrading a server is known as "forklifting" it.
Pictures or it didn't happen. :-P
Actually, I was just thinking about how many scrap PCs you could
scavenge and wire together to make a cluster. I wonder how much old junk
you would need to even come close to the processing power of a single
high-spec PC?
> And you know, I really, really miss SQL. :-)
Even if it does violate the relational model? Aww, it must be wuv...
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Le 2012-01-16 15:03, Stephen a écrit :
> On 16/01/2012 7:12 PM, Tom Austin wrote:
>> But the cheap hardware fails often and requires more manpower to manage
>> and replace it.
>
> Jobs! :-D
>
No. He died a while back.
--
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/* flabreque */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/* @ */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/* gmail.com */}camera{orthographic location<6,1.25,-6>look_at a }
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>> Jobs! :-D
>
> No. He died a while back.
Oldies but goldies...
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On 18/01/2012 1:42 PM, Francois Labreque wrote:
> Le 2012-01-16 15:03, Stephen a écrit :
>> On 16/01/2012 7:12 PM, Tom Austin wrote:
>>> But the cheap hardware fails often and requires more manpower to manage
>>> and replace it.
>>
>> Jobs! :-D
>>
>
> No. He died a while back.
>
Jobbies! Then. :-P
--
Regards
Stephen
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On 1/13/2012 2:07 PM, Tom Austin wrote:
>
> So now the hunt - why did winbind die......
>
>
>
It died because I made a small configuration change.
I did not make a backup of the config file because I was making a very
simple change that was very easily undoable.
Just a simple x = y line.
Well, in VI I hit i too many times and that little extra 'i' got added
to the domain for winbind - in a hard to see place.
So, lesson learned - no matter how simple the modification - always make
a copy that you can fall back to that is UNMODIFIED from what works.
At least now I have a simple smb.conf for sharing files in an emergency.
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On Wed, 18 Jan 2012 09:06:13 +0000, Invisible wrote:
> Pictures or it didn't happen. :-P
http://www.youtube.com/watch?v=zRwPSFpLX8I perhaps?
Jim
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> Pictures or it didn't happen. :-P
They're out there.
>> And you know, I really, really miss SQL. :-)
> Even if it does violate the relational model? Aww, it must be wuv...
Far better than what you get to use at Google. :-)
--
Darren New, San Diego CA, USA (PST)
People tell me I am the counter-example.
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>> Pictures or it didn't happen. :-P
>
> http://www.youtube.com/watch?v=zRwPSFpLX8I perhaps?
...the HELL?! o_O
1. I had no idea they had this many computers.
2. I had no idea it required engineering on this scale to run that many
computers.
3. That seems like quite a lot of empty space, actually...
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On 20/01/2012 9:12 AM, Invisible wrote:
>>> Pictures or it didn't happen. :-P
>>
>> http://www.youtube.com/watch?v=zRwPSFpLX8I perhaps?
>
> ....the HELL?! o_O
>
Nor am I out of it. ;-)
> 1. I had no idea they had this many computers.
>
http://news.cnet.com/8301-1001_3-10209580-92.html
> 2. I had no idea it required engineering on this scale to run that many
> computers.
>
It is not a domestic operation.
> 3. That seems like quite a lot of empty space, actually...
It does not mean that it is wasted space, though. You need space for
construction and maintenance. Not to mention air flow for cooling.
--
Regards
Stephen
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>> 1. I had no idea they had this many computers.
>>
> http://news.cnet.com/8301-1001_3-10209580-92.html
My God. o_O
>> 2. I had no idea it required engineering on this scale to run that many
>> computers.
>
> It is not a domestic operation.
Sure. But given that computers are very low-power devices, you don't
think of a computer plant as something requiring megawatts of power and
entire rooms of cooling equipment.
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On 20/01/2012 10:18 AM, Invisible wrote:
>
> Sure. But given that computers are very low-power devices, you don't
> think of a computer plant as something requiring megawatts of power and
> entire rooms of cooling equipment.
I would not say that computers are *very* low-power devices. As it said
in the article the containers have a power consumption that can reach
250 kilowatts. So you only need 4 containers to have to supply a
megawatt of power. Then add the cooling requirements and the utilities
and it all adds up.
--
Regards
Stephen
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On 20/01/2012 11:20 AM, Stephen wrote:
> On 20/01/2012 10:18 AM, Invisible wrote:
>>
>> Sure. But given that computers are very low-power devices, you don't
>> think of a computer plant as something requiring megawatts of power and
>> entire rooms of cooling equipment.
>
> I would not say that computers are *very* low-power devices. As it said
> in the article the containers have a power consumption that can reach
> 250 kilowatts. So you only need 4 containers to have to supply a
> megawatt of power. Then add the cooling requirements and the utilities
> and it all adds up.
Compared to an industrial cement kiln or a smelting works, a computer
uses virtually zero power.
The difference, of course, is that we're not talking about a computer.
We're talking about *thousands* of computers. Much like a light bulb
uses almost no power, but the entire Blackpool illuminations probably
use quite a bit of power...
I'm not saying it's wrong, I'm saying it's surprising.
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On 20/01/2012 11:31 AM, Invisible wrote:
> I'm not saying it's wrong, I'm saying it's surprising.
Why do you think that it is surprising?
--
Regards
Stephen
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On 20/01/2012 01:08 PM, Stephen wrote:
> On 20/01/2012 11:31 AM, Invisible wrote:
>> I'm not saying it's wrong, I'm saying it's surprising.
>
> Why do you think that it is surprising?
Or, to put it another way, why do you *not* think it's surprising?
I guess once you already know something, it probably doesn't surprise
you any more...
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On 20/01/2012 1:10 PM, Invisible wrote:
> On 20/01/2012 01:08 PM, Stephen wrote:
>> On 20/01/2012 11:31 AM, Invisible wrote:
>>> I'm not saying it's wrong, I'm saying it's surprising.
>>
>> Why do you think that it is surprising?
>
> Or, to put it another way, why do you *not* think it's surprising?
>
I have worked in heavy industry and when I worked offshore on production
platforms I was familiar with most aspects of utilities.
> I guess once you already know something, it probably doesn't surprise
> you any more...
That is true but if you stop and think (no slur intended) you might find
on reflection it is not really surprising. It is like doing a quick
mental calculation to see if an answer is in the correct range.
Guesstimate power requirements for 1 server = 200 Watts
Power for 1000 servers in a container (X 1000) 200 KW
Power for 12 containers = 2.4 MW. See no surprise. ;-)
--
Regards
Stephen
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>> I guess once you already know something, it probably doesn't surprise
>> you any more...
>
> That is true but if you stop and think (no slur intended) you might find
> on reflection it is not really surprising. It is like doing a quick
> mental calculation to see if an answer is in the correct range.
> Guesstimate power requirements for 1 server = 200 Watts
> Power for 1000 servers in a container (X 1000) 200 KW
> Power for 12 containers = 2.4 MW. See no surprise. ;-)
I guess the thing is, most people will never, ever see 1000 computers...
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On Fri, 20 Jan 2012 09:12:41 +0000, Invisible wrote:
>>> Pictures or it didn't happen. :-P
>>
>> http://www.youtube.com/watch?v=zRwPSFpLX8I perhaps?
>
> ...the HELL?! o_O
>
> 1. I had no idea they had this many computers.
It hit a number of the sites a couple years ago (see the date on the
video)
> 2. I had no idea it required engineering on this scale to run that many
> computers.
You've got to manage them *somehow*, right?
> 3. That seems like quite a lot of empty space, actually...
You have to circulate air to keep things cool. Overheating in such an
environment could be a serious problem.
Jim
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On Fri, 20 Jan 2012 10:18:25 +0000, Invisible wrote:
> Sure. But given that computers are very low-power devices, you don't
> think of a computer plant as something requiring megawatts of power and
> entire rooms of cooling equipment.
I've done work in a 20,000 sq. ft. data center. Data centers are big
business these days.
Jim
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On 1/20/2012 2:18, Invisible wrote:
> Sure. But given that computers are very low-power devices, you don't think
> of a computer plant as something requiring megawatts of power and entire
> rooms of cooling equipment.
Each of those containers has over 1000 computers in it. There's 50
containers in this one building. (That's a small building for Google.) This
is from 2005 or so, when computers weren't as efficient. So how much power
do you think it takes to run 50,000 computers, plus air conditioning for
them, if each has (say) 150W power supply?
--
Darren New, San Diego CA, USA (PST)
People tell me I am the counter-example.
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Le 20/01/2012 18:02, Jim Henderson a écrit :
>> > 2. I had no idea it required engineering on this scale to run that many
>> > computers.
> You've got to manage them *somehow*, right?
>
Wondering if they are running MS Windows:
1. Did they get a rebate on number of license ?
2. In case of security update, did they all update & reboot at the same
time ?
Obviously, they are not using Apple's computers.
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On 20/01/2012 05:03 PM, Jim Henderson wrote:
> On Fri, 20 Jan 2012 10:18:25 +0000, Invisible wrote:
>
>> Sure. But given that computers are very low-power devices, you don't
>> think of a computer plant as something requiring megawatts of power and
>> entire rooms of cooling equipment.
>
> I've done work in a 20,000 sq. ft. data center. Data centers are big
> business these days.
The biggest data center I've ever been in was one largish room populated
with server racks.
Heh, I still remember looking at one of the stacks, and seeing that it
had *seven* 4.2 GB drives in it. (Remember, in 1997, those suckers where
EXPENSIVE.) I remember feeling slightly giddy trying to compute how much
total storage space such a monster RAID setup... Ah, the memories.
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On 21/01/2012 05:42 PM, Darren New wrote:
> On 1/20/2012 2:18, Invisible wrote:
>> Sure. But given that computers are very low-power devices, you don't
>> think
>> of a computer plant as something requiring megawatts of power and entire
>> rooms of cooling equipment.
>
> So how
> much power do you think it takes to run 50,000 computers, plus air
> conditioning for them, if each has (say) 150W power supply?
As I say, the point is that most people will never see 50,000 computers
in one place all at once.
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On 23/01/2012 07:23 AM, Le_Forgeron wrote:
> Wondering if they are running MS Windows:
> 1. Did they get a rebate on number of license ?
> 2. In case of security update, did they all update& reboot at the same
> time ?
>
> Obviously, they are not using Apple's computers.
I'm pretty certain it all runs Linux. (I seem to recall a Google paper
about how they made various improvements to the Linux kernel to handle
SCSI error conditions better or something like that...) I have no idea
*which* Linux, of course... It's quite possible that it's something that
does cost money.
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On 1/15/2012 6:05 AM, Orchid XP v8 wrote:
>>> And also I'm assuming this is not cheap, so management do not want.
>>
>> Making something truly zero down-time is exceedingly expensive.
>
> Yeah, reducing down-time isn't usually too bad, but /zero/ down-time
> requires going to absurd lengths.
When I was stationed at Onizuka AFB, California (the Blue Cube, for
those who live or work near the south end of the San Francisco Bay), we
had two large SATCOM dishes, called Sun East and Sun West.
One chronic problem was that getting downtime for preventive maintenance
was as difficult as pulling gold teeth from a chicken. The user
community (who was and always will be better connected than the
maintenance community) were as stubborn as mules about allowing any
downtime for any reason.
"Hey, what if we took each dish down, once every six months, and do all
of the preventive maintenance specified in the technical orders?"
"No, no, we need those dishes up 24/7. Denied."
You'll never guess what the result was.
Regards,
John
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On Mon, 23 Jan 2012 09:31:05 +0000, Invisible wrote:
> On 21/01/2012 05:42 PM, Darren New wrote:
>> On 1/20/2012 2:18, Invisible wrote:
>>> Sure. But given that computers are very low-power devices, you don't
>>> think of a computer plant as something requiring megawatts of power
>>> and entire rooms of cooling equipment.
>>
>> So how much power do you think it takes to run 50,000 computers, plus
>> air conditioning for them, if each has (say) 150W power supply?
>
> As I say, the point is that most people will never see 50,000 computers
> in one place all at once.
That isn't really necessary to be able to do the math....
Jim
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On Mon, 23 Jan 2012 09:29:40 +0000, Invisible wrote:
> On 20/01/2012 05:03 PM, Jim Henderson wrote:
>> On Fri, 20 Jan 2012 10:18:25 +0000, Invisible wrote:
>>
>>> Sure. But given that computers are very low-power devices, you don't
>>> think of a computer plant as something requiring megawatts of power
>>> and entire rooms of cooling equipment.
>>
>> I've done work in a 20,000 sq. ft. data center. Data centers are big
>> business these days.
>
> The biggest data center I've ever been in was one largish room populated
> with server racks.
>
> Heh, I still remember looking at one of the stacks, and seeing that it
> had *seven* 4.2 GB drives in it. (Remember, in 1997, those suckers where
> EXPENSIVE.) I remember feeling slightly giddy trying to compute how much
> total storage space such a monster RAID setup... Ah, the memories.
Indeed, I still recall that the Fortune 50 company I worked for a decade
ago had an EMC storage array with 750 GB of storage in it....
My new *laptop* has a drive that big in it. I've got about 4 TB of
storage here at home now.
Jim
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On Mon, 23 Jan 2012 08:23:08 +0100, Le_Forgeron wrote:
> Le 20/01/2012 18:02, Jim Henderson a écrit :
>>> > 2. I had no idea it required engineering on this scale to run that
>>> > many computers.
>> You've got to manage them *somehow*, right?
>>
>>
>
> Wondering if they are running MS Windows:
> 1. Did they get a rebate on number of license ?
Google? Run Windows? No, they use a custom OS AFAICR.
Jim
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>> Heh, I still remember looking at one of the stacks, and seeing that it
>> had *seven* 4.2 GB drives in it. (Remember, in 1997, those suckers where
>> EXPENSIVE.) I remember feeling slightly giddy trying to compute how much
>> total storage space such a monster RAID setup... Ah, the memories.
>
> Indeed, I still recall that the Fortune 50 company I worked for a decade
> ago had an EMC storage array with 750 GB of storage in it....
>
> My new *laptop* has a drive that big in it. I've got about 4 TB of
> storage here at home now.
The fun thing is, apparently SSD has
1. Reached price levels where Normal Humans can potentially afford them.
2. Reached capacities where you might actually buy this stuff.
Interesting times ahead, eh?
(Personally, I still can't figure out why SSD isn't several /million/
times faster than a mechanical spinning disk, but hey...)
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>>> So how much power do you think it takes to run 50,000 computers, plus
>>> air conditioning for them, if each has (say) 150W power supply?
>>
>> As I say, the point is that most people will never see 50,000 computers
>> in one place all at once.
>
> That isn't really necessary to be able to do the math....
Sure, that's the great thing about math; it always works right, unlike
intuition. ;-)
But it's not a calculation most people would bother to make, because the
power consumption of a PC is "negligible".
In a similar vein, the heat output of a normal human in a large empty
room is also negligible. But weirdly, if you put /a lot/ of humans in a
room, no matter how big that room is, they manage to raise the
temperature of the whole room. Unexpected, but true...
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On Mon, 23 Jan 2012 15:41:25 +0000, Invisible wrote:
>>> Heh, I still remember looking at one of the stacks, and seeing that it
>>> had *seven* 4.2 GB drives in it. (Remember, in 1997, those suckers
>>> where EXPENSIVE.) I remember feeling slightly giddy trying to compute
>>> how much total storage space such a monster RAID setup... Ah, the
>>> memories.
>>
>> Indeed, I still recall that the Fortune 50 company I worked for a
>> decade ago had an EMC storage array with 750 GB of storage in it....
>>
>> My new *laptop* has a drive that big in it. I've got about 4 TB of
>> storage here at home now.
>
> The fun thing is, apparently SSD has
>
> 1. Reached price levels where Normal Humans can potentially afford them.
>
> 2. Reached capacities where you might actually buy this stuff.
>
> Interesting times ahead, eh?
Indeed, I've a friend in Scotland who has a Thinkpad with an SSD in it
and the performance is good, but the battery life is also quite good (I
think he said he gets 10 hours out of a single battery).
Jim
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>> The fun thing is, apparently SSD has
>>
>> 1. Reached price levels where Normal Humans can potentially afford them.
>>
>> 2. Reached capacities where you might actually buy this stuff.
>>
>> Interesting times ahead, eh?
>
> Indeed, I've a friend in Scotland who has a Thinkpad with an SSD in it
> and the performance is good, but the battery life is also quite good (I
> think he said he gets 10 hours out of a single battery).
Lots of laptops have offered an SSD option for a while now. The problem
has always been that the price is a bit insane. Looks like prices are
starting to become reasonable now - although I see 100x differences in
the reported I/O performance being quoted for different models. (!!)
Also, I'm quite impressed with my own laptop. Usually laptops /claim/ to
run for 8 hours or something, but /actually/ run for about 20 minutes.
The 8 hours figure applies only if you leave the laptop turned on but
not *doing* anything. :-P But my current laptop /really does/ run for
several hours without needing recharging. It's pretty neat...
(My laptop also has /actual 3D performance/ too. I had no idea laptops
could do that now!)
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On 23/01/2012 3:43 PM, Invisible wrote:
> Unexpected, but true...
<boggle>
--
Regards
Stephen
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On Mon, 23 Jan 2012 15:50:19 +0000, Invisible wrote:
>>> The fun thing is, apparently SSD has
>>>
>>> 1. Reached price levels where Normal Humans can potentially afford
>>> them.
>>>
>>> 2. Reached capacities where you might actually buy this stuff.
>>>
>>> Interesting times ahead, eh?
>>
>> Indeed, I've a friend in Scotland who has a Thinkpad with an SSD in it
>> and the performance is good, but the battery life is also quite good (I
>> think he said he gets 10 hours out of a single battery).
>
> Lots of laptops have offered an SSD option for a while now. The problem
> has always been that the price is a bit insane. Looks like prices are
> starting to become reasonable now - although I see 100x differences in
> the reported I/O performance being quoted for different models. (!!)
>
> Also, I'm quite impressed with my own laptop. Usually laptops /claim/ to
> run for 8 hours or something, but /actually/ run for about 20 minutes.
> The 8 hours figure applies only if you leave the laptop turned on but
> not *doing* anything. :-P But my current laptop /really does/ run for
> several hours without needing recharging. It's pretty neat...
>
> (My laptop also has /actual 3D performance/ too. I had no idea laptops
> could do that now!)
My new laptop has 3D performance as well - it's a "desktop replacement".
But I typically get about 2-3 hours off the battery in powersave mode.
Most laptops that I've used for a bit, the battery typically is good for
about an hour to an hour and a half. But a new battery generally will do
well.
Jim
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On Mon, 23 Jan 2012 15:43:34 +0000, Invisible wrote:
>>>> So how much power do you think it takes to run 50,000 computers, plus
>>>> air conditioning for them, if each has (say) 150W power supply?
>>>
>>> As I say, the point is that most people will never see 50,000
>>> computers in one place all at once.
>>
>> That isn't really necessary to be able to do the math....
>
> Sure, that's the great thing about math; it always works right, unlike
> intuition. ;-)
>
> But it's not a calculation most people would bother to make, because the
> power consumption of a PC is "negligible".
Actually not so much. A 450 W power supply draws a reasonably
significant amount of power.
> In a similar vein, the heat output of a normal human in a large empty
> room is also negligible. But weirdly, if you put /a lot/ of humans in a
> room, no matter how big that room is, they manage to raise the
> temperature of the whole room. Unexpected, but true...
Not unexpected at all - completely rational and in line with the laws of
thermodynamics.
Jim
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>> But it's not a calculation most people would bother to make, because the
>> power consumption of a PC is "negligible".
>
> Actually not so much. A 450 W power supply draws a reasonably
> significant amount of power.
Yeah, generally you only find power supplies that meaty on high-end
"leet gamer" PCs. I'm guessing Google doesn't use those.
Even 450W is peanuts compared to what my kettle uses. (3.6 kW)
>> In a similar vein, the heat output of a normal human in a large empty
>> room is also negligible. But weirdly, if you put /a lot/ of humans in a
>> room, no matter how big that room is, they manage to raise the
>> temperature of the whole room. Unexpected, but true...
>
> Not unexpected at all - completely rational and in line with the laws of
> thermodynamics.
Sure. But humans don't think in terms of thermodynamics, they think in
terms of common everyday experience.
Random fact: If you're dangling from a wire above a pit of molten lava,
YOU DIE. In particular, you do /not/ have to actually *touch* the lava
for it to kill you. An entire lake radiates easily enough heat to cook a
small elephant, never mind your skinny arse. And that's without even
taking into account convection and all the toxic gasses.
Really, that scene from Indiana Jones and the Temple of Doom is
laughably implausible... But most people actually have no clue exactly
how hot lava really is. It's not in their everyday experience.
Actually, going back to my previous point: The amount of /moisture/
emitted by a normal human is absurdly small. And yet, put enough of them
in a room, and it can get astonishingly moist in there! o_O
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Invisible <voi### [at] dev null> wrote:
> >> Heh, I still remember looking at one of the stacks, and seeing that it
> >> had *seven* 4.2 GB drives in it. (Remember, in 1997, those suckers where
> >> EXPENSIVE.) I remember feeling slightly giddy trying to compute how much
> >> total storage space such a monster RAID setup... Ah, the memories.
> >
> > Indeed, I still recall that the Fortune 50 company I worked for a decade
> > ago had an EMC storage array with 750 GB of storage in it....
> >
> > My new *laptop* has a drive that big in it. I've got about 4 TB of
> > storage here at home now.
>
> The fun thing is, apparently SSD has
>
> 1. Reached price levels where Normal Humans can potentially afford them.
Yep, I own two of them. A 60GB as a system drive for my desktop and a 120GB for
my laptop.
The performance improvement really is remarkable. And its not the burst speed
that is interesting but the random access transfer rates.
> 2. Reached capacities where you might actually buy this stuff.
>
> Interesting times ahead, eh?
>
> (Personally, I still can't figure out why SSD isn't several /million/
> times faster than a mechanical spinning disk, but hey...)
The read performance is actually mostly limited by the host interface (SATA3 is
up to 600MB/s nowadays) and the memory management of the SSD, write perfomance
largely depends on how fast the flash cells can be programmed.
Regards
Aydan
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Invisible <voi### [at] devnull> wrote:
> Actually, going back to my previous point: The amount of /moisture/
> emitted by a normal human is absurdly small. And yet, put enough of them
> in a room, and it can get astonishingly moist in there! o_O
I just had a look in Wikipedia:
1m³ of air at 20 can carry roughly 30ml of water (as vapour).
1 human sweats about 400ml to 1l per day.
Since "normal" room air usualy has about 50% humidity that leaves about 15ml/m²
for the sweat. That would mean 1 human can saturate 1 - 2.5 m³ of air per hour.
Now you just need the number of people and the size of the room to know how fast
it saturates.
Regards
Aydan
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On 23-1-2012 11:38, John VanSickle wrote:
> On 1/15/2012 6:05 AM, Orchid XP v8 wrote:
>>>> And also I'm assuming this is not cheap, so management do not want.
>>>
>>> Making something truly zero down-time is exceedingly expensive.
>>
>> Yeah, reducing down-time isn't usually too bad, but /zero/ down-time
>> requires going to absurd lengths.
>
> When I was stationed at Onizuka AFB, California (the Blue Cube, for
> those who live or work near the south end of the San Francisco Bay), we
> had two large SATCOM dishes, called Sun East and Sun West.
>
> One chronic problem was that getting downtime for preventive maintenance
> was as difficult as pulling gold teeth from a chicken. The user
> community (who was and always will be better connected than the
> maintenance community) were as stubborn as mules about allowing any
> downtime for any reason.
>
> "Hey, what if we took each dish down, once every six months, and do all
> of the preventive maintenance specified in the technical orders?"
>
> "No, no, we need those dishes up 24/7. Denied."
>
> You'll never guess what the result was.
Difficult.
my first guess would be that after 9-12 months the system failed for
more than twice the time of the provocative maintenance.
but...
you said I couldn't guess. so that is not what happened.
ergo, the system was reliably working for 10 years until it was replaced
by a better system with a small overlap in time.
...
No that can not be right, because if that was the case I guessed it, and
I couldn't.
...
but, but, that would be true of every other guess...
...
...
Ah, I got it, I can not *guess* it, therefore I must *know* the answer:
After 9-12 months the system failed for more than twice the time of the
provocative maintenance.
--
tip: do not run in an unknown place when it is too dark to see the
floor, unless you prefer to not use uppercase.
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On 23-1-2012 16:43, Invisible wrote:
>>>> So how much power do you think it takes to run 50,000 computers, plus
>>>> air conditioning for them, if each has (say) 150W power supply?
>>>
>>> As I say, the point is that most people will never see 50,000 computers
>>> in one place all at once.
>>
>> That isn't really necessary to be able to do the math....
>
> Sure, that's the great thing about math; it always works right, unlike
> intuition. ;-)
>
> But it's not a calculation most people would bother to make, because the
> power consumption of a PC is "negligible".
>
> In a similar vein, the heat output of a normal human in a large empty
> room is also negligible. But weirdly, if you put /a lot/ of humans in a
> room, no matter how big that room is, they manage to raise the
> temperature of the whole room. Unexpected, but true...
<boggle indeed>
I think the rule of thumb is that a person is about 100W. but any amount
of power will heat any room even if only slighly unless:
a) the room is infinite in size
b) the room was warmer than a person to begin with (i.e. warmer than a
person that is not cooled by outside temperatures)
--
tip: do not run in an unknown place when it is too dark to see the
floor, unless you prefer to not use uppercase.
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On Mon, 23 Jan 2012 12:22:44 -0500, Aydan wrote:
> Invisible <voi### [at] devnull> wrote:
>> Actually, going back to my previous point: The amount of /moisture/
>> emitted by a normal human is absurdly small. And yet, put enough of
>> them in a room, and it can get astonishingly moist in there! o_O
>
> I just had a look in Wikipedia:
> 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
> 1 human sweats about 400ml to 1l per day.
> Since "normal" room air usualy has about 50% humidity that leaves about
> 15ml/m² for the sweat. That would mean 1 human can saturate 1 - 2.5 m³
> of air per hour.
> Now you just need the number of people and the size of the room to know
> how fast it saturates.
You'd also need to know the current relative humidity to know how
saturated it is before you start adding people to the room.
0% humidity is quite rare - in fact, I don't know that it's possible on
Earth other than in an artificial environment. I live in a desert
climate (though not in the desert), and while we do easily hit below 20%
relative humidity, we don't hit 0. (In fact, it's snowing right now)
Jim
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On 23/01/2012 05:22 PM, Aydan wrote:
> Invisible<voi### [at] devnull> wrote:
>> Actually, going back to my previous point: The amount of /moisture/
>> emitted by a normal human is absurdly small. And yet, put enough of them
>> in a room, and it can get astonishingly moist in there! o_O
>
> I just had a look in Wikipedia:
> 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
20 what?
> 1 human sweats about 400ml to 1l per day.
You probably need to take breath moisture into account as well.
Even so, 1l/day is 41ml/hour - which is minute.
> Since "normal" room air usualy has about 50% humidity that leaves about 15ml/m²
> for the sweat. That would mean 1 human can saturate 1 - 2.5 m³ of air per hour.
> Now you just need the number of people and the size of the room to know how fast
> it saturates.
I would suggest that sweat varies by temperature too. ;-)
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On 23/01/2012 08:35 PM, andrel wrote:
> I think the rule of thumb is that a person is about 100W.
That sounds like quite a lot...
...until you realise that 100W of heat is actually a very small amount.
It takes 3.6 kW just to boil a small puddle of water inside an enclosed
space (i.e., my kettle), and it takes several minutes to do that.
> but any amount
> of power will heat any room even if only slighly unless:
>
> a) the room is infinite in size
> b) the room was warmer than a person to begin with (i.e. warmer than a
> person that is not cooled by outside temperatures)
You forgot "unless the heat escapes the room faster than the heat source
adds it". I've certainly seen houses so poorly insulated that short of a
lava pit, the rooms are doomed to be at thermal equilibrium with the
outside world.
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Invisible <voi### [at] devnull> wrote:
> On 23/01/2012 05:22 PM, Aydan wrote:
> > Invisible<voi### [at] devnull> wrote:
> >> Actually, going back to my previous point: The amount of /moisture/
> >> emitted by a normal human is absurdly small. And yet, put enough of them
> >> in a room, and it can get astonishingly moist in there! o_O
> >
> > I just had a look in Wikipedia:
> > 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
>
> 20 what?
centigrade.
> > 1 human sweats about 400ml to 1l per day.
>
> You probably need to take breath moisture into account as well.
>
> Even so, 1l/day is 41ml/hour - which is minute.
It's not so minute if a m³ of air can only carry 30ml at 20°C total. Or 15ml
with a base humidity of 50%
> > Since "normal" room air usualy has about 50% humidity that leaves about 15ml/m²
> > for the sweat. That would mean 1 human can saturate 1 - 2.5 m³ of air per hour.
> > Now you just need the number of people and the size of the room to know how fast
> > it saturates.
>
> I would suggest that sweat varies by temperature too. ;-)
and activity and ...
Regards
Aydan
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On 1/23/2012 3:25 PM, andrel wrote:
> On 23-1-2012 11:38, John VanSickle wrote:
>> On 1/15/2012 6:05 AM, Orchid XP v8 wrote:
>>>>> And also I'm assuming this is not cheap, so management do not want.
>>>>
>>>> Making something truly zero down-time is exceedingly expensive.
>>>
>>> Yeah, reducing down-time isn't usually too bad, but /zero/ down-time
>>> requires going to absurd lengths.
>>
>> When I was stationed at Onizuka AFB, California (the Blue Cube, for
>> those who live or work near the south end of the San Francisco Bay), we
>> had two large SATCOM dishes, called Sun East and Sun West.
>>
>> One chronic problem was that getting downtime for preventive maintenance
>> was as difficult as pulling gold teeth from a chicken. The user
>> community (who was and always will be better connected than the
>> maintenance community) were as stubborn as mules about allowing any
>> downtime for any reason.
>>
>> "Hey, what if we took each dish down, once every six months, and do all
>> of the preventive maintenance specified in the technical orders?"
>>
>> "No, no, we need those dishes up 24/7. Denied."
>>
>> You'll never guess what the result was.
>
> Difficult.
> my first guess would be that after 9-12 months the system failed for
> more than twice the time of the provocative maintenance.
> but...
> you said I couldn't guess. so that is not what happened.
> ergo, the system was reliably working for 10 years until it was replaced
> by a better system with a small overlap in time.
> ...
> No that can not be right, because if that was the case I guessed it, and
> I couldn't.
> ...
> but, but, that would be true of every other guess...
> ...
> ...
> Ah, I got it, I can not *guess* it, therefore I must *know* the answer:
> After 9-12 months the system failed for more than twice the time of the
> provocative maintenance.
While I was stationed there the systems were down around 5% to 10% of
the time.
Regards,
John
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On 1/23/2012 5:53 PM, Jim Henderson wrote:
> On Mon, 23 Jan 2012 12:22:44 -0500, Aydan wrote:
>
>> Invisible<voi### [at] devnull> wrote:
>>> Actually, going back to my previous point: The amount of /moisture/
>>> emitted by a normal human is absurdly small. And yet, put enough of
>>> them in a room, and it can get astonishingly moist in there! o_O
>>
>> I just had a look in Wikipedia:
>> 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
>> 1 human sweats about 400ml to 1l per day.
>> Since "normal" room air usualy has about 50% humidity that leaves about
>> 15ml/m² for the sweat. That would mean 1 human can saturate 1 - 2.5 m³
>> of air per hour.
>> Now you just need the number of people and the size of the room to know
>> how fast it saturates.
>
> You'd also need to know the current relative humidity to know how
> saturated it is before you start adding people to the room.
>
> 0% humidity is quite rare - in fact, I don't know that it's possible on
> Earth other than in an artificial environment. I live in a desert
> climate (though not in the desert), and while we do easily hit below 20%
> relative humidity, we don't hit 0. (In fact, it's snowing right now)
>
> Jim
Cave system near here is.. damn close. Was going to be used as a bomb
shelter, by the government, but, frankly, they would have had to store
20 times the water they still have down there to survive it. You can
definitely tell there is next to no water in the air while there.
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On Tue, 24 Jan 2012 15:12:43 -0700, Patrick Elliott wrote:
> On 1/23/2012 5:53 PM, Jim Henderson wrote:
>> On Mon, 23 Jan 2012 12:22:44 -0500, Aydan wrote:
>>
>>> Invisible<voi### [at] devnull> wrote:
>>>> Actually, going back to my previous point: The amount of /moisture/
>>>> emitted by a normal human is absurdly small. And yet, put enough of
>>>> them in a room, and it can get astonishingly moist in there! o_O
>>>
>>> I just had a look in Wikipedia:
>>> 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
>>> 1 human sweats about 400ml to 1l per day.
>>> Since "normal" room air usualy has about 50% humidity that leaves
>>> about 15ml/m² for the sweat. That would mean 1 human can saturate 1 -
>>> 2.5 m³ of air per hour.
>>> Now you just need the number of people and the size of the room to
>>> know how fast it saturates.
>>
>> You'd also need to know the current relative humidity to know how
>> saturated it is before you start adding people to the room.
>>
>> 0% humidity is quite rare - in fact, I don't know that it's possible on
>> Earth other than in an artificial environment. I live in a desert
>> climate (though not in the desert), and while we do easily hit below
>> 20%
>> relative humidity, we don't hit 0. (In fact, it's snowing right now)
>>
>> Jim
> Cave system near here is.. damn close. Was going to be used as a bomb
> shelter, by the government, but, frankly, they would have had to store
> 20 times the water they still have down there to survive it. You can
> definitely tell there is next to no water in the air while there.
Vegas reportedly sees a low-ish average of 11%. As I recall, you're not
far from there (south, I think), about equidistant from Phoenix and Vegas?
Jim
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On 1/24/2012 3:25 PM, Jim Henderson wrote:
> On Tue, 24 Jan 2012 15:12:43 -0700, Patrick Elliott wrote:
>
>> On 1/23/2012 5:53 PM, Jim Henderson wrote:
>>> On Mon, 23 Jan 2012 12:22:44 -0500, Aydan wrote:
>>>
>>>> Invisible<voi### [at] devnull> wrote:
>>>>> Actually, going back to my previous point: The amount of /moisture/
>>>>> emitted by a normal human is absurdly small. And yet, put enough of
>>>>> them in a room, and it can get astonishingly moist in there! o_O
>>>>
>>>> I just had a look in Wikipedia:
>>>> 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
>>>> 1 human sweats about 400ml to 1l per day.
>>>> Since "normal" room air usualy has about 50% humidity that leaves
>>>> about 15ml/m² for the sweat. That would mean 1 human can saturate 1 -
>>>> 2.5 m³ of air per hour.
>>>> Now you just need the number of people and the size of the room to
>>>> know how fast it saturates.
>>>
>>> You'd also need to know the current relative humidity to know how
>>> saturated it is before you start adding people to the room.
>>>
>>> 0% humidity is quite rare - in fact, I don't know that it's possible on
>>> Earth other than in an artificial environment. I live in a desert
>>> climate (though not in the desert), and while we do easily hit below
>>> 20%
>>> relative humidity, we don't hit 0. (In fact, it's snowing right now)
>>>
>>> Jim
>> Cave system near here is.. damn close. Was going to be used as a bomb
>> shelter, by the government, but, frankly, they would have had to store
>> 20 times the water they still have down there to survive it. You can
>> definitely tell there is next to no water in the air while there.
>
> Vegas reportedly sees a low-ish average of 11%. As I recall, you're not
> far from there (south, I think), about equidistant from Phoenix and Vegas?
>
> Jim
Yeah, but this underground system also has "zero" water in it, and the
rock seems to suck up what little comes in from outside, so.. its pretty
damn nasty.
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On Tue, 24 Jan 2012 16:13:01 -0700, Patrick Elliott wrote:
> Yeah, but this underground system also has "zero" water in it, and the
> rock seems to suck up what little comes in from outside, so.. its pretty
> damn nasty.
I was a bit surprised that death valley wasn't listed as drier.
Jim
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>> Yeah, but this underground system also has "zero" water in it, and the
>> rock seems to suck up what little comes in from outside, so.. its pretty
>> damn nasty.
>
> I was a bit surprised that death valley wasn't listed as drier.
Apparently some of the driest places on Earth are the dry valleys of the
South Pole. Sure, /most/ of Antarctica is under miles of solid ice. But
there are a few valleys utterly bare of snow, deep in the interior of
the continent. Apparently they can go /centuries/ without any
precipitation at all.
How dry the *air* is, I couldn't say...
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On 1/22/2012 23:23, Le_Forgeron wrote:
> Wondering if they are running MS Windows:
It's Linux, with each application on any given box running in its own VM,
which is also Linux. Unless you need Windows or OSX (e.g., testing
javascript code against IE), in which case your code runs on the appropriate
server farm.
> 2. In case of security update, did they all update& reboot at the same
> time ?
No, they do rolling restarts.
> Obviously, they are not using Apple's computers.
Not in the data centers, no.
--
Darren New, San Diego CA, USA (PST)
People tell me I am the counter-example.
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