getting quote together for rack build

[Uranium-235]

so, i'm getting this together for a company, and i'm using this board /w a c2d E8400

http://www.newegg.com/Product/Produc...82E16813182143

and i'm paring it up with 2 SATA RE3's and this power supply

http://www.newegg.com/Product/Produc...82E16817338047

My question, is, well, will this PSU draw more then 500W even with both plugged in and running? I'm trying to find a good rackmount UPS and i'm not sure if I would need 2000W plus. I'm sure it draws a little more then 500W but i'm not sure its 1000W total. I'm just covering my bases and trying to make sure I don't f this up

[NxB]

Re: getting quote together for rack build

Will this be the only system in the rack? Any other stuff like routers, kvm, etc? 1000w is pretty puny.

[Uranium-235]

Re: getting quote together for rack build

nope, another one just like it. its a small rack, one PBX and one file host

what i'm asking is will a dual redundant 500W draw more then 500? will it draw double?

[NxB]

Re: getting quote together for rack build

This might help you:

http://forums.hexus.net/hexus-hardwa...r-results.html

[Uranium-235]

Re: getting quote together for rack build

thank you, that does help but here is my problem

if he motherboard draws say, 300w, will it run each PSU at 300W? (remember this is a redundant power supply)

[Th3_uN1Qu3]

Re: getting quote together for rack build

Well, grab a dictionary and look for the meaning of redundant. A redundant power supply means that it is failure proof in that if one of the two PSUs fail, the other one takes over. Basically you have one supply sitting idle waiting for the other one to fail, hence it uses zero power while doing that. If the first supply fails, then the second one will use up exactly the same amount of power that the first was previously using.

Besides, 300+300 can't equal 300 anyway. So if the motherboard ate 300W and the supplies were in parallel, then it would use 150W off each. But as i explained above, this isn't the case.

[PCBONEZ]

Re: getting quote together for rack build

That's not how it works.
They are auctioneered.
They share the load and if one craps out the load simply shifts to the good one.
20/80 or 30/70 is more realistic than 50/50 sharing though because the PSU's aren't going to be exactly identical no matter how hard they try.
.

[Th3_uN1Qu3]

Re: getting quote together for rack build

Hmm. So they don't trust them to switch on fast enough eh?

[brethin]

Re: getting quote together for rack build

It depends on the subsystem, some can be managed the one you linked just load shares.
With a managed subsystem you can control what each PSU does and when.

[PCBONEZ]

Re: getting quote together for rack build

Hmm. So they don't trust them to switch on fast enough eh?

No.
Internal redundant supplies aren't like grid back-up power.

They are connected directly to the mobo.
Switching takes too long and results in a spike which would [or could] result in a system crash.

Grid backup systems have the UPS between them and mobo which can take the load long enough for switch to do the shift and which will filter [buffer] out the spike.

[PCBONEZ]

Re: getting quote together for rack build

what i'm asking is will a dual redundant 500W draw more then 500? will it draw double?

No.
Power supplies don't 'push' power.

If your system uses 200 watts you could connect 10 PSU's in parallel to it and the system will still only use 200 watts which would be distributed across those 10 PSU's.
If 9 of the PSU's fail the load simply shifts to the 10th PSU which has to provide all 200 watts.
-
The down side is the PSU efficiency would really suck because of all the components that are powered up but not really doing much of anything.

-
-
You could take two standard ATX PSU's and make them redundant by adding a diode in each wire and then connecting them to the same load.
The diodes prevent power from one PSU from feeding back into the other PSU if one of them fails due to an internal short.
Diodes used that way are the simplest form of a DC power auctioneer.
.
.

[PCBONEZ]

Re: getting quote together for rack build

A -fully- redundant power system would have each of those redundant PSUs powered by different generators and ideally the generators would be in different geographic locations. [One may be a local generator.]

That is what they do it in Nuclear Power and it's the preferred way to set up a Data Center. If you go shopping for a hosted server you will see some that 'brag' about being connected to two of more power companies [or their own generators] and/or that they are connected to two of more ISPs. [Because redundancy for ISP's works on the same principal.]
.

[PCBONEZ]

Re: getting quote together for rack build

You could take two standard ATX PSU's and make them redundant by adding a diode in each wire and then connecting them to the same load.
The diodes prevent power from one PSU from feeding back into the other PSU if one of them fails due to an internal short.
Diodes used that way are the simplest form of a DC power auctioneer.
.
.

The ground wires should also have diodes BTW...

[Uranium-235]

Re: getting quote together for rack build

thanks for the info guys. Hmm, do you think a 300W redundant will run that E8400 and two RE3's?

[Th3_uN1Qu3]

Re: getting quote together for rack build

Yes.

[Uranium-235]

Re: getting quote together for rack build

one board I am getting for the router is this:

http://www.newegg.com/Product/Produc...82E16813138150

I notice several KZG's, should I bother replacing them after I get it? do you think KZG has gotten it right by 2010? (i'm sure when they initially developed this board). I bet I should replace the ones with vents (long as I do i with new caps from tc)

[PCBONEZ]

Re: getting quote together for rack build

Total watts isn't enough information to know for sure.
- There are a lot of 300 watt redundant PSUs still on the market that were designed for P3 and have next to nothing on +12v.

So, need to check amps on each rail and the combined 3.3v & 5v, then look at how much you will pull on each rail.

To estimate CPU amps draw on PSU take TDP, multiply by 1.5, then divide by volts on the rail. [+12v in this case.]
The 1.5 compensates for VRM efficiency and assumes it's 67% to be conservative.
[65% isn't uncommon on older boards and is possible current cheap boards. Most newer boards [that say, which ain't many] have VRM efficiency between 70&75%.]

Drives use both +12v and +5v, just read the amps off the drives.
Fans are generally on +12v and can add up if the server chassis has a cubic butt-ton of them.

You need to look at video power too especially if using an add-in.
Hungry video chips can use a lot of +12v.
Mediocre Integrated [in chipset] video is loosely around 40 watts on Intel chipset boards but it varies and so does where the power comes from. [Which rail.]

Assume 2 amps on +5v and 2 amps on +3.3v per installed add-in card.
[That's the limit of the -slots- which is used because cards do not say how much they use. It's not likely a card will actually use that but assuming it will gives a safety margin.]

-
KZG & KZJ were never good and they are now out of production so they never will be.
If you want it to last get rid of them.
.

[PCBONEZ]

Re: getting quote together for rack build

I have a few NOS redundants around that don't have jobs.
Among them is a 460 watt Zippy/Emacs that might be perfect depending on the chassis.
I'll PM you.

[Uranium-235]

Re: getting quote together for rack build

the 3.3 & 5 is 160 total

the c2d 8400 is 65w.

so 65 * 1.5 / 12 = ~8.125?

[goodpsusearch]

Re: getting quote together for rack build

Is this true? They stopped making KZG and KZJ?