[mythtv-users] Backend hardware advice - Power usage

[Dave Johnson]

Out of curiosity, I¹ll get my Kill-a-Watt out and check the total power
usage of my storage system.  For those interested in how much their
equipment is costing them, this baby is well worth the 30 bucks:

Kill-a-Watt: 
http://www.amazon.com/gp/product/B0001EY6P0/104-0010433-4125511?v=glance&n=2
28013

I bought it at work because we have a ³wiring closet² doing double-duty as
our server room and we are very constrained by both power and cooling
capacity and needed to balance all the UPSs  (1500va is max for ³wiring
closet² use in San Francisco) across the circuits as well as consider
ditching any inefficient equipment if it didn¹t give us the bang/kWh we
needed and anything we could do to lower the 85-deg temp in the room
couldn¹t be bad.  This sucker made it a breeze to measure everything.

Interestingly, our three single-cpu 3.0 Xeon Dell PE1850 servers from a year
ago with 2x10kRPM 36GB drives each consume about the same power as  while
our three Opteron 275 dual-cpu BL35p blade servers (1x 60GB PATA 2.5² drive
ea), while these three Opteron dualies do about 4 times the work each (!)

Speaking of power savings, we recently purchased two of the Nexsan
SATABeast¹s for our SAN storage and d2d backup and they support both full
spin-down of drives as well as a unique feature that allows the drives to
spin to approx 1/2-speed with less than 2 seconds recovery time.  Pretty
sweet.  Yeah, like I said, bang/kWh is the new buzz for everyone.  It¹s
about time.

I¹ll post when I get those numbers.  It would be interesting to see what
numbers others out there have for their systems.  If there¹s enough
interest, I can put a wiki up for people to post their power consumption
numbers... we¹ll see.

ŒNite,

-Úve


From: John Drescher <drescherjm at gmail.com>
Reply-To: Discussion about mythtv <mythtv-users at mythtv.org>
Date: Sun, 16 Jul 2006 23:42:02 -0400
To: Discussion about mythtv <mythtv-users at mythtv.org>
Subject: Re: [mythtv-users] Backend hardware advice - RAID suggestions

I see a big problem with these calculations. You are assuming that the
system is not running any type of power saving mode. For current
athlon64/opteron processors with cool and quiet running the processor will
consume around 25W.

Also at work I have an opteron 248 server with 4GB of PC3200 ECC DDR, dual
processor board, 2 power supplies and 18 X 250 GB  WD SATA drives and the
entire system draws ~300W under full load as reported by the apc ups that it
is connected. 

John

On 7/16/06, Brad Templeton <brad+myth at templetons.com> wrote:
> On Fri, Jul 14, 2006 at 08:03:08PM -0700, dave johnson wrote:
>> > -11x200GB Seagate 7200.8 PATA HD ($43/ea - massive tripple-rebate
>> coupon-hell at Fry's and a lot of
>> > trust-worthy friends.  It took almost 3 months to get the rebates and one
>> was denied because I
>> > probably filled one out wrong, so add $70 for "my mistake." ;)
> 
> 
> How many watts are these drives?   Typically one sees 7 to 15w for such drives
> (slower
> drives, 4500 or 5400 rpm are usually better - quieter, cooler, lower power,
> longer life). 
> 
> With your two PSs how much power are you drawing for the whole system?  200 to
> 300
> watts?  More?
> 
> In California (you said you went to Fry's) incremental power has gotten up to
> 19 cents/kwh.
> 
> That means 300 watts, running 24/7 costs $500 per year.   (In winter you save
> a bit 
> from the heat it gives you, but not a lot.  In summer you may be paying it
> back
> in AC costs if you need AC.)
> 
> Even in places with cheaper 10 cent/kwh power, it's still almost $250 per year
> for
> the power.
> 
> Forget about the damage to the environment, 11x200gb is just a bad way to do
> it
> from an economic standpoint.    They have 500gb drives in Fry's for $175 I
> think.
> 
> So 5x500gb could do 2 TB RAID-5 if you really need RAID (you don't in my view,
> this is 
> not a system that needs 100% availability) for a bit more money ($875 for
> drives vs.
> $540 for the 11x200gb without doing rebates, and without 2 power supplies
> 
> But more to the point it would draw a lot less power, and make up the
> difference 
> in a year or so.   Quieter and smaller too.
> 
> 
>> > Never under estimate the power of the K.I.S.S. method :)
> 
> Never forget that power is becoming the most expensive component of any
> always-on PC,
> especially in California and other places with expensive power.
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> mythtv-users at mythtv.org
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> 


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