HP Power Calculators

A while back I mentioned a meeting I'd had with HP regarding Green IT (and in my case specifically storage). As part of the discussion, I asked Lucio Furlani (VP for Marketing in TSG) if we could have Power Calculations for HP storage.

Well, true to their word, HP promised and have now delivered the first of a number of storage Power Calculators, available here: http://egui-prod.houston.hp.com/eGlue/eco/begin.do.

The first calculator is for the EVA4400 and there are more to follow. Get on-line and have a look and feed back what you think!

On the power calculator front, EMC, HDS (and now HP) all produce power tools for their storage products. EMC and HDS need to step up and make their tools public to anyone - after all if you believe your product is superior, then you've nothing to hide.

Does anyone know of calculators for IBM, 3Par, Pillar, Netapp etc?

RTFM

Quite a while back, I posted on the Green Datacentre. Actually, the post was over a year ago and datacentre power and cooling issues have become a really hot (sic) issue.

However, I have to castigate myself severely for not Reading the Flaming Manual. In particular the power demands of the Cisco 9513 switch. Really the problem comes from working in an environment where power/cooling isn't wasn't an issue - just whack it in and get the electricians to provision whatever power you need. No need to actually validate the power requirements - just overprovision and everything will be fine. But recently, I wanted to power a 9513 up outside the datacentre to do pre-installation checks. The question was, could I power it up from a normal 13A socket? With 6000W of power required, surely not! Well, this is where RTFM comes in.

Thumbing through the 95xx Installation Guide I found that the chassis and fan trays take 318 watts, supervisor cards take 126 watts each and the biggest module, 48 port line-cards, 195 watts each. Therefore a fully populated 9513 would require 2715 watts. Based on UK power supplies of 240V, that's just over 11 amps. So, technically (although I wouldn't advise it and probably wouldn't try it) a 13A power supply would suffice.

So what's with the 6000W power supply? In fact, the power supplies in the 9513 are 6000W *capable* but don't have to demand or supply that level of power. Each takes two power feeds (from separate PDUs hopefully) and if only one feed is available, the power supply can only provide 2900W. If you think about it, what that means is that overall, 2 power supplies can provide ample power to run the switch without being under stress (and therefore provide more consistent, smooth power). Should a PDU fail, then each PSU can supply 2900W, again easily enough to run the whole switch. If *at the same time* one PSU should also fail, the remaining power supply can still run the whole switch. It may not be a desirable situation but it is possible. In terms of what power/cooling requirement should be catered for, it is actually a maximum of 2715 watts.

It just shows what reading the manual can do for you.

The Power Question

I've seen a lot of discussion (and I think a bit of a theme at SNW) on power consumption in datacentres. Obviously the subjects of global warming and increased energy prices have put the subject at the centre of focus. But I think when datacentres are being built, there isn't an issue. The problem comes along as the datacentre fills up with equipment. Invariably, new equipment (especially in the storage world) is coming in denser and requiring more power per rack or square metre. So, as equipment is swapped out and replaced, the original calculations done on how much power per square metre is needed are no longer accurate and the balance tips from one of "have we got the space" for new equipment to one of "can we power the new kit up".

I don't see how this problem will be solved as datacentre planners will always cater for the power/cooling of today's products, not the mythical power demands of future products. Datacentres will therefore have a finite life, after which you may as well start again.

Here's a practical example; There is a manufacturer of highly dense storage arrays (that don't need to be powered up all the time) who can't deploy into a number of London datacentres I know because product density would cause the array to fall to the floor. The datacentres were never designed to take products of that weight...