SNIA presents spec for green-storage power measurement

Spec divides storage systems into categories and measures idle power in gigabytes per watt

Driven to cut energy consumption in the datacenter and server room, companies are becoming increasingly interested in the amount of power their IT hardware consumes. Yet organizations face the ongoing challenge of coming up with meaningful energy-consumption metrics for complex machinery like servers, networking gear, or storage equipment.

One organization stepping up to the challenge is the Storage Networking Industry Association (SNIA). The group this week released its initial GSI (Green Storage Initiative) Green Storage Power Measurement Specification for public review and comment, designed to help organizations measure the energy consumption of storage systems. By some estimates, storage accounts for as much as 30 percent of the power consumption in the datacenter, by no means a trivial amount.

[ SNIA isn't the only organization working on power-measurement standards. One has already been presented for networking gear. ]

The specification includes a Green Storage Taxonomy for classifying storage products based on energy consumption characteristics and application environments, as well as a standard for collecting idle power consumption measurements for storage systems. That is, this specification only looks at how much power a storage device is using when it's at rest, not when it's working; the latter measurement should come later this year.

To ensure fair apples-to-apples comparison between similar storage gear, the Green Storage Taxonomy classifies systems based on feature criteria for the application environments that they are intended to support. The application environments are divided into five categories, ranging from small home/office applications to larger enterprise-oriented applications. The categories covered in online, near-online, removable media libraries, non-removable media libraries, infrastructure appliances, and infrastructure switches.

The feature criteria for each category are based on the required level of data protection, component redundancy, serviceability, data-access time, and range of energy consumption.

The categorization is essential in ensuring apt comparisons among different systems' energy usage. For example, it would be meaningless to compare the energy consumption of a disk system to a tape system, or to compare the performance of a mid-range SAN to an enterprise-level SAN.

In attention to providing the taxonomy for classifying storage systems, SNIA has devised an Idle Power Measurement specification, outlining a standard for testing and measuring storage power consumption at idle. The idle power measurements are reported in raw gigabytes per watt.

Measurements are based on such factors as raw storage capacity, storage media RPM and interface of each type of storage media within the storage device, the number of enclosures/systems in the online or near-online taxonomy category, and the number of tape drives for systems in the removable-media library taxonomy category.

Throughout the year, SNIA's GSI intends to expand the Green Storage Power Measurement Specification to include development of standardized active power measurement guidelines and metrics and storage-system power-supply-efficiency specs. The group will also promote and publish each vendor's completed test metrics.

The detailed SNIA Green Storage Power Measurement Specification, including the Green Storage Taxonomy, can be found here.