I recall ten years ago standing at the back of a rented 42U cabinet in large data center, staring as the entire stack of servers suddenly lost power. I had just plugged two new servers into the cabinet’s power feed. I was following a then-common method of power planning: adding servers until the circuit breaker tripped.
The only other method available to me was to guess: I could look at the wattage printed on each power supply faceplate, and estimate that my server would consume perhaps half of that. Much to the chagrin of the colocation facility operators, I preferred the plug-until-it-blows technique.
Things have gotten a little safer nowadays. Vendors are producing server power calculators that can help you compute the power consumption of specific server configurations. All major vendors publish these calculators, and they’re easy to use (and also abuse). Operating them is fairly simple, and unlike most vendor-provided total-cost-of-ownership (TCO) tools, these power calculators feature a pleasant lack of vendor hype; they are primarily tools created by engineers for engineers.
In this post, I’ll talk about the basic feature sets of power calculators and some of the differences from vendor to vendor. In a follow-up post, I’ll suggest some important do’s and don’ts for using these tools.
Calculator Feature Sets
The basic operation of power calculators is very similar. You specify a server model, define the type and count of memory, processors, and hard drives, and then get an estimate of the watts that configuration might consume.
(Click on image above to enlarge, or view in GoogleDocs)
These calculators generally only cover servers. You’ll probably have to obtain power estimates for storage and networking gear elsewhere.
Unique Traits of Each Tool: Cisco UCS Power Calculator
New (January 2012) Cisco UCS Power Calculator added airflow details
In addition to providing power estimates for servers, the Cisco Power Calculator also includes the Fabric Interconnects. For blades, the calculator limits you to the number of servers you can connect to one fabric interconnect (or pair of interconnects for redundancy).
The calculator allows you specify your anticipated server utilization (“% CPU Usage”), and then reports power at that point as well as at idle and maximum. By default, the calculator shows you power at 50% utilization. One piece of Cisco's documentation recommends that you focus on the 50% number from the calculator. The idea is that few end users can match the floating-point and memory intensive workload that corresponds to the max-power estimate. As I’ll explain in Part 2 of this blog post, that’s probably pretty good advice for all of the calculators.
Although you can export the tool’s results as an Excel spreadsheet, it uses an awkward export process that actually downloads a small Windows executable onto your local machine; that executable then creates the Excel file.
IBM Power Configurator (x86) and IBM Energy Estimator
Power Configurator (left) is a Windows executable that covers x86 and blade servers. Energy Estimator (right) is for Power servers, and shows a simple utilization vs. energy plot in its results.
IBM has different calculators for each of its server families. There's one for System x (which includes all BladeCenter products), one for Power Systems, and one for System z (which is not public).
The IBM System x and BladeCenter Power Configurator is a downloadable Windows executable named PowerProg.exe. It's easy to use and conveniently covers server models going back to 2002. (Most of the other calculators go back only one or two generations.) A nifty feature is the "Choose Max Configuration" button, a shortcut to identifying the worst-case server configuration. One warning about this program: the README file says that you must have Microsoft Excel loaded on your local desktop for it to work.
Unlike IBM's System x power calculator, the calculator for Power Systems is a based on a simple HTML form. It's called the IBM Systems Energy Estimator; IBM uses the word "energy" in this calculator rather than "power" to avoid confusion with its “Power” brand. A useful feature in this calculator – and one not available in any other – is that it gives an estimate for the impact of power saving modes on power use.
Oracle (Sun) Calculators
Oracle (Sun) Calculators Would Make Sgt. Joe Friday Proud: Just the Facts, Ma’am.
Oracle's calculators for Sun servers are very Spartan; they’re simple HTML forms, one per server model. (There’s also a single form that covers populated blade enclosures.) While these basic tools lack some features, Oracle’s calculators are often posted on the same day that products are announced, which is much earlier than other vendors usually provide calculator data. Oracle also uses the same tool format for its storage products, so you don’t have to hunt down other tools to find how much power your disk enclosures will use.
Dell Energy Smart Solution Advisor
If This was a Contest, I’d Give Dell’s Comprehensive ESSA the Top Trophy
Dell’s Energy Smart Solution Advisor (ESSA) is the only stand-alone power calculator that includes complete configuration checking rules. It uses exactly the same rules set that Dell’s online store uses. So, while other power calculators contain some configuration checking, I’ve often found discrepancies in what those power calculators allow versus what the vendors’ configuration guides say. (A common example is DIMMs; I’ve occasionally found power calculators that allow invalid DIMM configurations or prohibit configurations that are actually valid.) ESSA is also unique in that it lets you pick a workload type, and it will adjust results accordingly.
ESSA is easily the most comprehensive of the power calculators. However, my colleague Miles Oliver points out that the breadth of ESSA’s features can make it overcomplicated. For example, the calculator spits out configuration warnings irrelevant to power consumption, such as when it cautions you that you’ve forgotten to include the correct documentation DVDs in a configuration. Another example of possible overdesign is the exported Excel spreadsheets, which have a pretty awkward format if you just want to play with the numbers in Excel.
Dell’s unusual implementation of one feature also deserves note: to save (and later reload) your solutions, you must create an account on Dell.com.
HP Power Advisor
I Like the GUI for HP Power Advisor; I’d Love to See the “Recommendations” Tab Completed
HP's Power Advisor is the only calculator offered both in a web-based form and as a downloadable executable. A graphical display "fills" rack cabinets as you add servers and blades. A great feature of this calculator is its inclusion of HP part numbers in exported reports. There are also some intriguing, but as yet unimplemented features, such as a tab that offers recommendations for alternative configurations that might be more power-efficient. HP even has a Twitter account specifically for its Power Advisor: @hppoweradvisor.
HP warned me that if I wanted to consistently load and restore configurations I should use the downloadable version of the tool rather than the web-based one, due to occasional errors. However, as long as I saved configurations in Power Advisor's .hpa format, I had no problems loading and restoring my files from either version.
Fujitsu M-Series and Fujitsu SystemArchitect
The Simple HTML-Based M-series calculator (left). The calculator for PRIMERGY Servers (right) Is Embedded in Fujitsu’s System Configuration Tool
Fujitsu’s calculator for M-Series SPARC (left above) is very similar to the calculators from Oracle. It’s a simple, web-based form that produces a single power number. To access them, visit the main information page for each server, then look for the calculator link.
For the x86 PRIMERGY servers, the power calculator is integrated into Fujitsu’s general server configuration tool, SystemArchitect. That’s very forward-thinking on the part of Fujitsu; for one thing, Fujitsu customers and partners have to learn only a single tool. SystemArchitect is a very powerful tool for building, validating, and pricing Fujitsu server and storage solutions. As a complete configuration tool, it’s in a completely different class than the power-only calculators described in this blog post. (For example, in addition to providing power numbers, SystemArchitect can recommend power cabling and validate PDU configurations – a feature that perfectly complements a power calculator.)
In my next post, I'll give some power calculator Do's and Don'ts, and talk about where the data in power calculators comes from and how accurate it is.
Reference: Links to Server Vendor Power Calculators
- Cisco UCS Power Calculator
- Dell Energy Smart Solution Advisor
- Fujitsu M Series (calculator links on each server page)
- Fujitsu SystemArchitect
- HP Power Advisor
- IBM Systems Energy Estimator (Power servers)
- IBM Power Configurator (System x and BladeCenter)
- Oracle (Sun) calculators (one per server)
Some additional calculators that cover older servers:
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