Hi all

know that the rep for dell boxes is that they are a little power hungry, but wanted to know in peoples experience what sort of power draw we should expect on:
1850 - single xeon, 2 10k scsi drives
as above with dual psu
2850 - single xeon, 4 10k drives + dual psu
as above with dual xeons

according to dell rack advisor, 2 x 1850 and 1 x 2850 draws 7.4A, which seems pretty high if 8a feeds for a rack are common and 16a seems to be the max before you start endangering the air con capabilities.

Are dell's REALLY that hungry, or are there more realistic power consumption figures I should use?

Yes, they really do eat a lot of power. Possibly they are advising start up surge power though, as that figure does seem a tad on the heavy side.

Most people who actually want to get anywhere near to a full rack of kit need 16A as minimum, unless you're installing P2's in tower cases

Originally Posted by stevebaker

according to dell rack advisor, 2 x 1850 and 1 x 2850 draws 7.4A, which seems pretty high if 8a feeds for a rack are common and 16a seems to be the max before you start endangering the air con capabilities.

Did the advisor ask what exact spec servers to come up with that figure? It could be they are quoting maximum possible usage with eg. dual CPUs of the fastest spec available, all drive bays full using 15K disks and dual PSUs.

I think the enterprise kit such as Dell and HP does tend to be quite power hungry but then they are offering equipment that is well specced to handle fully loaded configurations.

Drawing a current of 7.4A is huge... that's 1.5KW... most likely a start up peak current, in my personal opinion but I'm prepared to be wrong (and surprised!)

nop, it didnt ask specs, but I have since b een in touch with Dell reps and was quoted 330w for single xeon 1850 with 2x73gb scsi 10krpm drives + dual psu, and 542 for single xeon 2850 with 4 x scsi drives + dual psu
works out at 5.2a, which still seems high, although not quite as 1 cab per server bad!

anyone got any real world experience of power with 1850s / 2850s and raid + dual psu?
or is it the dual psu that is soaking the power? are they not master / slave, so apart from any power drained by the psu (ie heat lost in transforming the voltage), the server shouldnt drain any more than a single psu machine? (ie power only really means energy transformed, mainly into heat from the processor, or mechanical spinning in the discs, then the power cant suddenly get eaten??)

When those 3 servers are running they will use no more then 3Amps. Its just the starting current that will cause a spike (so turn them on one at a time leaving a few seconds between them).

The best way to find out running power is to use this: http://www.apc.com/tools/ups_selector/index.cfm
^ the APC tools is very very good.

I personally run a couple of PE1850's with dual everything and they don't use that much at all. The Ultra 320 SCSI disks eat up a lot of power.

Steve,

We've got spares of everything here - if you want an exact figure we'll plug the exact spec you're going for in and find out what the draw is.

One thing to remember is CPU running at 100% and drives constantly reading/writing will soak more power than idle components.

nsuk - thanks, that tool is great!
know that boot takes moe power, but just want to make sure that if we reboot servers at the same time or they all get maxed out (processor + hdd) then we will not suddently blow a circuit breaker (not much point on buying decent kit then chucking it all into an overcrowded, under powered data centre - would be better off under a desk!!)

anyone interested, the APC tool came back as 205W for the 1850, and 240W for the 2850.
Assuming the only way they got the data was try and see, so happy to rely on them, but thanks for the offer Ed

When turning on dell PE1850's & PE2850's you notice the fans and everything will go at super-speed (sounds like thing is going to take off) for about 5seconds... once this period is over the running power is what the APC selector says it is. To be honest, in a 11U 1/4 Rack you wouldn’t want more then 6 servers in there anyway and 8Amps (standard Redbus power supply size) would be plenty big enough for 6x high end dells.

Not quite sure how you are going to reboot 3/4 servers at the very same time, but if you are shutting down and rebooting within win2k3 svr then the dells don’t use any extra power its only when they are very first switched on do they max out. But thinking about it, the PE1850's have the PSU Fan(s) running even when they are switched off. I can't remeber what happens when you use a APC mastersiwtch on them... maybe somebody else knows?


Hope this is of a little help!