迈向高效能源管理：PUE新标准的未来趋势，您是否已做好准备

PUE是否已经老掉牙？

Is PUE too long in the tooth?

March 01, 2022

By Dan Swinhoe 

译 者 说

数据中心行业下一个能效指标会是什么？

What’s next for energy efficiency metrics in the data center industry?

LiquidStack

自Christian Belady和Chris Malone在2006年首次提出电能利用效率（PUE）并由绿色网格推广以来，电能利用效率（PUE）已成为衡量数据中心能效的事实指标。

Since it was first proposed by Christian Belady and Chris Malone and promoted by the Green Grid in 2006, power usage effectiveness (PUE) has become the de facto metric with which energy efficiency of data centers are measured.

它很容易计算—设施总功率与It负载消耗功率之间的比值—并提供了一个简单的单一指标，在非技术人群中广为人知。

It is easy to calculate – a ratio between total facility power and power consumed by the IT load – and it provides a simple single metric that can be widely understood by non-technical people.

但是，随着先进设施的PUE低于1.1时，越来越多的公司希望实现碳中和状态，现在是时候问一问了：我们应该继续延用PUE吗？如果是这样，该怎么办？

But as leading facilities move to PUEs below 1.1 and more companies look to achieve carbon-neutral status, it’s time to ask; should we move on from PUE? And if so, what to?

PUE：自身成功的受害者

PUE: a victim of its own success

在理想情况下，PUE将是1;进入数据中心的每kW能量将仅用于为IT硬件供电。虽然完美的1很可能无法实现，但能够快速、简单地测量能源使用情况并推动数据中心的改进。

In a perfect world, PUE would be 1; every kilowatt of energy coming into the data center would be used only to power the IT hardware. And while a perfect 1 is likely impossible, being able to quickly and easily measure energy use has driven improvements.

Uptime Institute表示，PUE的行业平均值已从2007年的2.5左右下降到今天的1.5左右。但即使是Uptime也表示，经过这么长时间，该指标看起来已经旧得“生锈了”。

The Uptime Institute says the industry average for PUE has dropped from around 2.5 in 2007, to around 1.5 today. But even Uptime has said the metric is looking ‘rusty’ after so long.

“自2016年绿色网格标准在ISO / IEC 30134-2：2016下发布以来，PUE一直是最流行，易于理解并因此广泛使用的指标之一，”Kao Data首席技术官Gérard Thibault说道。我认为，它的简单性一直是关键，在许多方面，客户将其作为一种衡量标准，以评估IT设备所消耗能源的有效成本收益，以及其可持续性。”

“PUE has been one of the most popular, easily understood and, therefore, widely used metrics since the Green Grid standard was published in 2016 under ISO/IEC 30134-2:2016,” says Gérard Thibault, CTO, Kao Data. “I believe that its simplicity has been key, and in many respects, customers use it as a metric to evaluate whether they are being charged cost-effectively for the energy their IT consumes and how sustainable they are.”

在一个有点复杂的行业中，PUE已被客户接受为能源效率的明确指标，并与可持续证书密闭可分。

“In an industry that is somewhat complex, PUE has become accepted by customers as a clear indicator of energy efficiency, becoming inextricably linked to sustainability credentials.”

然而，十多年后，PUE可能开始成为自身成功的受害者，工程公司Cundall（该公司的数据中心客户包括Facebook）的合伙人Malcolm Howe认为，PUE一直是该行业非常有益的工具。而且，在给其最初赋予的含义下，它推动了数据中心能效的显著提高，”他说。“人们很容易理解PUE最表层的意思，但当你深入到表层之下时，就会发现很多问题。

However, after more than a decade, PUE could be starting to become a victim of its own success, argues Malcolm Howe, Partner at engineering firm Cundall, whose data center clients include Facebook. “PUE has been an immensely beneficial tool for the industry. And in the guise of the role that it was originally intended for it has driven very significant improvements in energy efficiency in data centers,” he says. “People can quite readily get their heads around it on a very superficial level, but it's got loads of things wrong with it when you get below the surface.”

Boden数据中心,PUE为1.018

PUE的局限性

The limitations of PUE

随着我们接近常规冷却所能达到的极限，数据中心的业主和运营商希望实现碳中和甚至负碳，PUE开始失去其作为衡量标准的价值。

As we near the limits of what conventional cooling can achieve and data center owners and operators look towards carbon neutrality or even negativity, PUE starts to lose its value as a metric.

一些最高效的数据中心开始实现1.1或更低的PUE；由欧盟资助的瑞典BodenType数据中心的PUE为1.018，而华为称其模块化数据中心产品的PUE为1.111。谷歌表示，其大型设施全球平均为1.1，但能够低至1.07。

Some of the most efficient data centers are starting to achieve PUEs of 1.1 or lower; the EU-funded Boden Type data center in Sweden has recorded a 1.018 PUE, while Huawei claims its modular data center product has an annual PUE of 1.111. Google says its large facilities average 1.1 globally but can be as low as 1.07.

随着设施效率的提高，衡量PUE值的改进变得越来越困难，增加（投入）也越来越大。

As facilities become more efficient, measuring improvements with PUE becomes harder and gains become increasingly incremental.

我们现在的PUE降到了1.0；我们需要更精确的测量方法，“Howe说。“我们专注于努力实现这些可持续发展目标和净零排放，我们使用的是一种粗略的测量手段；我们使用的衡量标准并不能真正反映正在发生的事情的影响。

“We're now down to PUEs of 1.0-whatever; we need more precise methods of measurement,” says Howe. “We're focused on trying to achieve these sustainability targets and net-zero, and we're doing it with a tool that is a blunt instrument; we're using a metric that doesn't really capture the impact of what's going on.”

其直言不讳的一个例子是，PUE无法记录机架级别发生的事情。机架式UPS供电的IT电源或主板风扇;可以而且可能应该统计到耗能的表单中，但它没有。

An example of its bluntness is that PUE doesn’t capture what is happening at rack level. IT power to the rack can power rack level UPS or on-board fans; energy that could and probably should be added to the debit sheet, yet isn’t.

Howe 指出，在传统的风冷机架中，高达 10% 输送到 IT 设备的电力被服务器和 PSU 冷却风扇消耗。在他所说的“创意会计”中，一些公司可以通过这种方式使他们的 PUE 指标看起来更好。

Howe notes that in a conventional air-cooled rack, as much as 10 percent of the power delivered to the IT equipment is consumed by the server and PSU cooling fans. Some companies can make their PUE look better this way in what he describes as “creative accountancy.”

并非所有这些电能实际上都用于IT设备。我认为很多人都忽视了这一点，“他说。“许多典型的运营商将UPS放在机架里；他们可以通过将此UPS及其负载从基础设施能耗中移出并将其投入IT能耗，使其PUE值马上变得好看起来。你只是把它从电缆的一侧移动到另一侧，实际上并没有改变设施性能。

“Not all of that power is actually being used for IT. And I think a lot of people lose sight of that,” he says. “A lot of model operators putting UPS at rack level; they can immediately make their PUE look better by shifting the UPS load out of the infrastructure power and putting it into the IT power. You're just moving it from one side of the line to the other, you haven't actually changed the performance.”

PUE：一个营销指标

PUE a marketing metric

Howe还指出，PUE的简单性和在整个行业中的广泛使用，使得它不仅被用作内部改进指标，还被用作竞争中的优势武器。

Howe also notes that PUE’s simplicity and widespread use across the industry has led to it being used as a competitive advantage weapon as much as an internal improvement metric.

“随着时间的推移，它已经被当作一种营销工具，”他说。“运营商正在利用它来吸引客户，客户也乐得其所，并在RFP文件中给出最低PUE标准。

“Over time it has been seized upon as a marketing tool,” he says. “Operators are using it to bring in customers, and customers are going along with that and giving minimum PUE standards in the RFPs.”

许多运营商会很乐意吹捧其最新设施的PUE，并将其用作具有可持续发展意识的客户的诱饵。

Many operators will happily tout the PUE of their latest facilities, and use it as a lure for sustainability-conscious customers.

PUE从未真正用于此目的，它始终是一个改进指标，”他说，运营商应该“测量PUE，实施改造，然后再次测量以评估其有效性。它在行业内的重要性和形象从来不是刻意的，因为它并不真正适合此目的。

“PUE was never really intended for that, it was always an improvement metric,” He says operators should “measure the PUE, implement changes, and then measure it again to assess the effectiveness. “It’s taken on an importance and a profile within the industry that was never intended, for which it's not really suited.”

液冷与PUE

Liquid cooling and PUE

随着我们达到空气冷却的极限，液体冷却正成为一种越来越受欢迎和可行的替代方案。但随着使用率的增加，PUE作为衡量标准的有用性降低了

As we reach the limit of air cooling, liquid cooling is becoming an increasingly popular and feasible alternative. But as adoption increases, the utility of PUE as a yardstick lowers.

Howe说：“即使你有一个非常高效的风扇电机，它也会耗电。”。“我们已经达到了在空气冷却方面所能达到的物理极限。

“Even if you had a perfectly efficient fan motor, it is going to consume power,” says Howe. “We've got to the limit of what is achievable within the physics of what we've been doing with air cooling.”

在DCD的一篇评论文章中，Uptime Institute研究分析师Jacqueline Davis最近警告说，直接液体冷却（DLC）等技术深刻地改变了数据中心能耗的状况，并“严重破坏了”PUE作为基准工具的地位，甚至作为效率指标将“最终意味其过时”。

In an opinion piece for DCD, Uptime Institute research analyst Jacqueline Davis recently warned that techniques such as direct liquid cooling (DLC) profoundly change the profile of data center energy consumption and “seriously undermine” PUE as a benchmarking tool and even “eventually spell its obsolescence” as an efficiency metric.

“虽然DLC技术几十年来一直是一种成熟但小众的技术，但数据中心领域的一些人认为它即将得到更广泛的应用，”她说。“DLC重新定义了设施和IT基础设施的能耗构成，而不仅仅是将计算出的PUE降低到接近绝对极限。

“While DLC technology has been an established yet niche technology for decades, some in the data center sector think it’s on the verge of being more widely used,” she said. “DLC reshapes the composition of energy consumption of the facility and IT infrastructure beyond simply lowering the calculated PUE to near the absolute limit.”

Davis指出，大多数DLC实现通过降低设施功率实现了1.02至1.03之间的PUE。但它们也通过取消风扇来减少机架内部的能源需求—— 这一举措减少了能源浪费，但实际上也使PUE变得更糟。

Davis noted that most DLC implementations achieve a partial PUE of 1.02 to 1.03, by lowering the facility power. But they also reduce energy demands inside the rack by doing away with fans - a move that reduces energy waste, but also actually makes PUE worse.

“以目前的形式，PUE可能正在走向其生命的尽头，”她补充说。“PUE指标的弱化可能。。历史趋势的中断。此外，它将废掉竞争基准：所有DLC数据中心都将非常高效，没有实质性的能源差异。

“PUE, in its current form, may be heading toward the end of its usefulness,” she added. “The potential absence of a useful PUE metric would represent a discontinuity of historical trending. Moreover, it would hollow out competitive benchmarking: all DLC data centers will be very efficient, with immaterial energy differences.”

“对IT利用率的跟踪，以及对工作负载功耗的全面更精细的监控方法，可以量化能效收益，这比任何未来版本的PUE都要好得多。

“Tracking of IT utilization, and an overall more granular approach to monitoring the power consumption of workloads, could quantify efficiency gains much better than any future versions of PUE.”

Goonhilly数据中心的液冷设备

TUE：新的PUE，还是众多指标中的一个？

TUE: the new PUE or one metric among many?

如果PUE老掉牙了，是否有现成的替代品具有PUE的简单性，并且可以提供更好的前景？

If PUE really is too long in the tooth, is there a ready-made replacement that has the simplicity of PUE but can provide a better picture?

Howe表示，总电能利用效率（TUE）可以成为计算数据中心整体能源性能的更有效指标。TUE 通过 IT 电源使用效率 （ITUE） x PUE 进行计算。ITUE 考虑了机架级辅助组件（如服务器冷却风扇、电源单元和稳压器）的影响。TUE 是通过将 ITUE（特定于服务器的值）与 PUE（数据中心基础设施估值）相乘而获得的。

Howe says Total-Power Usage Effectiveness (TUE) can be a more effective metric at calculating a data center’s overall energy performance. TUE is calculated via IT Power Usage Effectiveness (ITUE) x PUE. ITUE accounts for the impact of rack-level ancillary components such as server cooling fans, power supply units and voltage regulators. TUE is obtained by multiplying ITUE (a server-specific value) with PUE (a data center infrastructure value).

“ITUE就像机架级别的PUE，以一种PUE本身无法解决的方式处理正在发生的事情。它说的是有多少能量将流向机架；这是有多少能量实际流向电子元件，”他说。

“ITUE is like a PUE at rack level and addressing what is going on in a way that PUE on its own does not. It's saying this is how much energy is going to the rack; and this is how much of that energy is actually going to the electronic components,” he says.

“它让你对这个层面上发生的事情有了更精确的理解。也就是说，你要么有一些服务于服务器风扇运转，要么你有一些介质泵，或者你有其他一些完全被动的东西。

“It's giving you a much more precise understanding of what's going on that level; which is you've either got some serving server fans spinning around or you've got some dielectric pumps, or you've got something else which may be completely passive.”

TUE和ITUE并不新鲜。Michael Patterson博士（英特尔公司）和能效HPC工作组（EEHPC WG）等。。约在十年前提出了这两个替代指标。

TUE and ITUE aren’t new; Dr. Michael Patterson (Intel Corp.) and the Energy Efficiency HPC Working Group (EEHPC WG) et al proposed the two alternative metrics around a decade ago.

与PUE相比，TUE的普及速度较慢。这些方程式并不难计算，但TUE需要对现有的IT硬件有更深入的了解，这是许多托管运营商无法满足的事情。

Compared to PUE, TUE’s adoption has been slow. The equations aren’t much harder to calculate, but TUE requires a greater understanding of the IT hardware in place – and that is something that many colo operators won’t have a lot of visibility into.

Howe表示，Cundall开始就TUE与客户进行沟通，并与客户一起从PUE转向PUE，部分原因是它希望确保其所有项目都朝着净零碳的方向发展，同时也是因为客户希望实现自己的可持续发展目标。

Howe says Cundall is starting to have conversations about TUE and moving on from PUE with its customers partly as it looks to ensure all its projects are heading towards net-zero carbon, but also as customers look to achieve their own sustainability goals.

随着越来越多的公司寻求部署液体冷却 - 这将超出PUE的衡量能力 - 越来越多的公司可能会选择TUE作为一种方式，以更好地说明其可持续性能力，因为大多数运行设施的PUE低于1.1。

As more companies look to deploy liquid cooling – which takes efficiency beyond PUE – more companies may opt for TUE as a way to better illustrate their sustainability credentials amid a landscape where most facilities operate at PUEs in the low 1.1s.

“运营商将希望尝试将自己定位为领先于行业，做得更多，实现更多目标。以前，人们一直在使用PUE相互比较，但现在你可能会让公司说“我的TUE是xx”。

“Operators are going to want to try and position themselves as being ahead of the game and doing more and achieving more. Previously, people have been comparing each other using PUE, but you might now get companies saying ‘my TUE is X’.”

PUE & TUE;只是更广泛的可持续发展指标的一部分

PUE & TUE; just parts of a wider sustainability picture

虽然TUE可以提供更精细的能源效率视图，但即使这样，它仍然只是整个可持续发展计划的一部分。没有一个指标可以全面反映出对数据中心可持续性的影响。

While TUE can provide a more granular view of energy efficiency, even then it is still just one part of the total sustainability package. There is no one metric to capture the entire picture of a data center’s sustainability impact.

许多大型运营商现在通过能源信贷和购电协议等方式抵消其能源使用，以确保直接由可再生能源为其供电运行，或至少与当地电网的同等能源相匹配。

Many of the large operators now offset their energy use with the likes of energy credits and power purchase agreements to ensure their operations are powered directly by renewable energy, or at least matched with equivalent energy contributing to local grids.

进一步来讲，谷歌和Aligned和T5等其他公司开始发布工具，可以更精确地显示各设施的能源使用情况，更准确地显示可再生能源每小时使用情况的指标。

Taking this further, Google and others such as Aligned and T5 are beginning to release tools that can show a more granular breakdown of energy use by facility, showing a more accurate picture of renewable energy use hour by hour.

公司越来越多地吹嘘其水利用效率（WUE）——该比率将每年现场用水量（以升为单位）除以IT设备用电量（以千瓦时为单位）——以说明其设施用水量是多么少。

Companies are increasingly touting their Water Usage Effectiveness (WUE) – a ratio which divides the annual site water usage in liters by the IT equipment energy usage in kilowatt-hours (KwH) – to illustrate how little water their facilities use.

碳利用效率（CUE）旨在衡量数据中心产生的二氧化碳排放量和IT设备的能耗。

Carbon Usage Effectiveness (CUE) aims to measure CO2 emissions produced by the data center and the energy consumption of IT equipment.

施耐德电气最近发布了一份框架文件，旨在帮助数据中心公司报告其环境影响，并评估其在可持续发展方面的进展。该白皮书超越了行业对PUE的正常关注，提出了23个指标中需要研究的五个工作领域。

Schneider Electric recently published a framework document designed to help data center companies to report on their environmental impact, and assess their progress towards sustainability. The paper goes beyond the industry's normal focus on PUE and sets out five areas to work on across 23 metrics.

“环境可持续性报告是许多数据中心运营商越来越关注的问题，”施耐德安全电源部门执行副总裁Pankaj Sharma当时告诉DCD。“然而，该行业缺乏实施、测量和报告环境影响的标准化方法。

“Environmental sustainability reporting is a growing focus for many data center operators," Pankaj Sharma, EVP of Schneider's secure power division, told DCD at the time. "Yet, the industry lacks a standardized approach for implementing, measuring, and reporting on environmental impact.

施耐德的23个指标中，包括温室气体（GHG）排放量（范围1、2和3）；现场和供应链用水；数据中心站点产生、填埋和转移的废料；甚至物种丰富度来衡量周围土地的生物多样性。

Amongst those 23 metrics, Schneider includes greenhouse gas (GHG) emissions (across Scopes 1, 2, and 3); water use, both on-site and in the supply chain; waste material from data center sites generated, landfilled, and diverted; and even species abundance to measure biodiversity in the surrounding land.

2020年，瑞士数据中心效率协会推出了SDEA标示，旨在以“端到端”的方式评估设施的效率和气候影响；不仅要考虑PUE，还要考虑基础设施利用率和现场的整体能源回收能力。

In 2020 the Swiss Datacenter Efficiency Association launched the SDEA Label, which aims to rate a facility’s efficiency and climate impact in an ‘end-to-end’ way; taking into account not only PUE but also infrastructure utilization and the site’s overall energy recycling capabilities.

尽管有年轻新贵的竞争，PUE目前似乎仍然是可持续发展指标中的佼佼者。

Despite the competition from young upstarts, PUE is still seemingly the top dog of sustainability metrics for now.

“在哈洛，我们以业界领先的效率水平运营，我们使用PUE帮助我们监控、测量和优化客户的能源足迹，”Kao的Thibault说。

“In Harlow, we operate at industry-leading levels of efficiency, and we use PUE to help us monitor, measure, and optimize our customers’ energy footprints,” says Kao’s Thibault.

“我们了解ITUE和TUE，但相信PUE仍然为我们的行业提供了一个被广泛接纳的指标，新的和旧的数据中心可以使用它来了解其能源需求，优化其ITE环境，减少浪费。

“We are aware of ITUE and TUE, but believe that PUE still offers our industry a widely adopted metric that can be used by new and legacy data centers to understand their energy requirements, to optimize their ITE environments, and reduce waste.”

“有人可能会说，我们的行业过于关注PUE，[但是]替代指标将需要更多的数据、参数和运营商与客户之间的讨论，以便定义新标准并推动落地。许多传统运营商除了提高PUE水平之外，可能没有更进一步方法，这是我们行业的另一个考虑因素。在该粒度级别可用之前，PUE仍是最佳选择。

“One might arguably say that our industry has been too focussed on PUE, [but] alternative metrics will require greater data, parameters, and discussion between operators and customers in order to define new standards and drive adoption. Many legacy operators also may not have the means to achieve anything further than improving PUE levels, which is another consideration for our industry. Until that level of granularity is available, PUE remains the best option.”

深 知 社

翻译：

李要铭

嘉兴银行数据中心基础设施主管

DKV（DeepKnowledge Volunteer）计划精英成员