[Novalug] Can you chain KVM switches??

Andrew Scott Beals andrew.beals@gmail.com
Fri Oct 7 14:43:42 EDT 2011


Kill A Watt is the canonical meter.  AMZN has them for about $22 most of the time.  

I have two machines, one a Compaq ML350G2 and a P4 (built for MythTV duty), both of which are of approximate Y2K1 vintage and both of which suck down 225 KVA when they're running.  The Compaq is a giant 5U rackable tower unit, and the P4 box is relatively quiet and will run OK in a space-restricted area (in an open-backed TV stand).  Before measuring them, I'd figured that the Compaq was the power pig, as not only does it have six 15k RPM disks spinning, it also has enormously-loud cooling fans.  

A EEE PC 900 (Centrino) netbook running ubuntu is 66 KVA at idle, surprisingly enough.  A Lenovo S10e (Atom N270) running OSX is 36.  The EEE has a 32GB SSD in it, the S10 is spinning a very large 2.5" hard drive and driving an external VGA display in addition to its internal display.


On Oct 7, 2011, at 11:24 AM, Ed James wrote:

> I use a "Kill-a-watt" meter
> 
> http://www.homedepot.com/buy/electrical/electrical-tools-accessories/kill-a-watt-83064.html
> 
> for stuff like that.  My P-IV costs about 80 bucks a year for 24x7
> use, but since I have
> electric heat during the heating season, the computer heat isn't
> wasted at all.  One thing
> thats kinda kewl about using the meter is seeing just how much power
> is used when
> your browser "rests" at a busy, javascript/flash/wotever heavy site,
> compared to resting
> at a plain old vanilla html page.  I've also discovered some of my own
> programs draining
> power like mad, until I tweaked them to drastically reduce power
> consumption.  We're
> talking the difference between virtually 100% CPU usage and 3-5% CPU
> usage with some
> minor tweaks.  Ya, we're all rich and can afford the power company
> payment, but when
> it's a laptop running on a UPS because the power lines are down, it
> really makes a
> difference.  I imagine portable device apps are in the same boat.
> 
> Ed James
> 
> On Fri, Oct 7, 2011 at 12:09 PM, daniel <daniel@yacg.com> wrote:
>> Oh I know what you mean.  Actually, I wondered that very thing, but one time
>> my wife went to Japan for a few months and I saw the biggest impact on the
>> electric bill -- not my server rack, but the laundry, dishes and A/C.  I
>> used a lot less of those and my power usage went near zero.
>> 
>> I think I will put some kind of meter on my power line to see what my rack
>> is pulling though... I am running one server with VMs inside at the moment.
>> 
>> 
>> 
>> On 10/07/2011 11:50 AM, Miles D. Oliver wrote:
>> 
>> This is understandable too and I hemmed over this same idea with KVM
>> switches for all my stuff but I wonder how much hardware a years worth of
>> power savings could buy with that many machines?
>> I'm no math wiz and it would take some time and a meter to get the facts and
>> in the end it may take a very long time to recoup the money spent on
>> hardware vs. the power consumption but it is worth doing the calculations.
>> I know I'm straying from the original ideas of the thread but is it worth to
>> doing the math on this problem if you can't get what you are after by trying
>> to mate all that hardware together.
>> 
>> 
>> On Fri, Oct 7, 2011 at 11:18 AM, daniel <daniel@yacg.com> wrote:
>>> 
>>> Heh... Given that he wants to string together old and inexpensive gear to
>>> make due, it's quite likely he doesn't have the resources to throw at doing
>>> it "a better way."
>>> 
>>> I know I have a pretty nice set up at home, but things have changed since
>>> I set it all up... I couldn't replace it if I needed to right now... as much
>>> as I would like to.
>>> 
>>> 
>>> On 10/07/2011 11:15 AM, Miles D. Oliver wrote:
>>> 
>>> One could ask why are you trying to do all this with physical machines now
>>> when stable virtual solutions exist?
>>> I had a similar setup a while ago and the noise, heat, and power
>>> consumption were all very annoying in my office to the point where I also
>>> had to have fans going when I was in there. It was ugly. I replaced all 6 of
>>> my machines, (Several Linux, 1 XP, 1 Sun)  with a single server running KVM
>>> and never looked back.   Its quieter, takes a lot less space, and is very
>>> noticeable in my monthly power bill.  I couldn't be happier.
>>> I also have the option of 'building' more machines with out any more
>>> noticeable impact. All that is in my office now is a simple NAS box and the
>>> server,  It was VERY liberating!!
>>> I can understand the desire to try and make what you have work and I
>>> resisted going virtual for a while but it was a great exercise and learning
>>> experience and I couldn't be happier.
>>> 
>>> 
>>> On Fri, Oct 7, 2011 at 11:01 AM, Beartooth <beartooth@beartooth.info>
>>> wrote:
>>>> 
>>>>       The subject asks it. I have a 4-port switch, which
>>>> handles the four PCs on my desk. (No shop near here carries
>>>> switches with more; and for the present purpose I doubt I'd
>>>> want to shell out for one if any did.)
>>>> 
>>>>       But I often, indeed usually, have a netbook a/o a laptop
>>>> running as well; and I own at least one more KVM switch which
>>>> has at least three working ports.
>>>> 
>>>>       If I were to run cables from, say, port #4 on the main
>>>> switch to another KVM switch, and from two of that one's ports to
>>>> the smaller machines, would that enable me to use my full-size
>>>> monitor and keyboard with them?
>>>> 
>>>>       Or would such an arrangement burn my laundry, quench my
>>>> fireplace, and run me down the street in front of a naked sword?
>>>> 
>>>> --
>>>> Beartooth Staffwright, Not Quite Clueless Power User
>>>> Remember I know little (precious little!) of where up is.
>>>> 
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>> 
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