How many Watts per Terabyte?

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Chuck Hollis makes some excellent points about Green Data Center Goes Marketing Mainstream. He does a great job summarizing EMC's strategy in this area:

1. Use VMware to virtualize your x86-based servers
2. Use more efficient disk media, such as high-capacity SATA disk drives

Both are great recommendations, but why limit yourself to what EMC offers? Your x86-based machines are only a subset of your servers,and disk is only a subset of your storage. IBM takes a more holistic approach, looking at the entire data center.

VMware

VMware is a great product, and IBM is its top reseller. But in addition to VMware, there are other solutions for the x86-based servers, like Xen and Microsoft Virtual Server. IBM's System p, System i, and System z product lines all support logical partitioning.

To compare the energy effectiveness of server virtualization, consider a metric that can apply across platforms. For example, for an e-mail server, consider watts per mailbox. If you have, say, 15,000 users, you can calculate how many watts you are consuming to manage their mailboxes on your current environment, and compare that with running them on VMware, or logical partitions on other servers. Some people find it surprising that it is often more cost-effective, and power-efficient, to run workloads on mainframe logical partitions (LPARs) than a stack of x86 servers running VMware.

More efficient Media

SATA and FATA disks support higher capacities, and run at slower RPM speeds, thus using fewer watts per terabyte.A terabyte stored on 73GB high-speed 15K RPM drives consumes more watts than the same terabyte stored using 500GB SATA.Chuck correctly identifies that tape is more power-efficient than disk, but then argues that paper is more power-efficient than tape. But paper is not necessarily more efficient than tape.

ESG analyst Steve Duplessie divides up data betweenDynamic vs. Persistent. The best place to put dynamic data is on disk, and here is where evaluation of FC/SAS versus SATA/FATA comes into play.Persistent data, on the other hand, can be stored on paper, microfiche, optical or tape media. All of these shelf-resident media consume no electricity, nor generate any heat that would require additional cooling.

A study by scientists at the Lawrence Berkeley National Laboratory titled High-Tech Means High-Efficiency: The Business Case for Energy Management in High-Tech Industries indicates thatData centers consume 15 to 100 times more energy per square foot than traditional office space. Storing persistent data in traditional office space can save a huge amount of energy. Steve Duplessie feels the ratio of dynamic to persistent data is 1:10 today, but is likely to grow to 1:100 in the near future, raising the demand for energy-efficient storage of persistent data ever more important to our environment.

Data centers consume nearly 5000 Megawatts in the USA alone, 14000 Megawatts worldwide. To put that in perspective, the country of Hungary I was in last week can generate up to 8000 Megawatts for the entire country (and they were using 7400 Megawatts last week as a result of their current heat wave, causing them grave concern).

Back in the 1990's, one of the insurance companies IBM worked with kept data on paper in manila folders, and armiesof young adults in roller skates were dispatched throughout the large warehouses of shelves to get the appropriate folder in response to customer service inquiries. Digitizing this paper into electronic format greatly reduced the need for this amount of warehouse space, as well as improved the time to retrieve the data.

A typical file storage box (12 inch x 12 inch x 18 inch) containing typed pages single-spaced, double-sided, 12 point font could hold perhaps 100MB. The same box could hold a hundred or more LTO or 3592 tape cartridges, each storing hundreds of GB of information. That's a million-to-one improvement of space-efficiency, and from a watts-per-TB basis, translates to substantial improvement in standard office air conditioning and lighting conditions.

technorati tags: IBM, EMC, Chuck Hollis, VMware, FC, SAS, SATA, FATA, disk, storage, logical partition, energy, power, cooling, Steve Duplessie, dynamic, persistent, data, Lawrence Berkeley National Laboratory, megawatt, paper, optical, microfiche, LTO, 3592, Project Big Green, Secondlife