Storage Soup

Oct 14 2009   8:51PM GMT

New standards emerge for power consumption testing and SAS connectivity

Beth Pariseau Beth Pariseau Profile: Beth Pariseau

In a week chock full of product news from Storage Networking World (SNW) and elsewhere, some new standards have slipped in under the radar that may become important once the dust settles.

The first of these is the announcement of a new Storage Performance Council (SPC) benchmark for testing the power consumption of storage devices in the data center. The new SPC-1E spec follows the SPC-1 C/E spec announced in June. Where the SPC-1C/E spec covered storage components and small subsystems (limited to a maximum of 48 storage devices in no larger than a 4U enclosure profile), the SPC-1E spec expands that support to include larger, more complex storage configurations.

According to an SPC presentation on the new benchmark,  “SPC-1/E is applicable to any SPC-1 storage
configuration that can be measured with a single SPC approved power meter/analyzer.”

For more on how the SPC-1C/E and SPC-1E benchmarks work, see our story on the SPC-1C/E announcement. Users should especially be aware of the parts of the benchmark calculation that can only be specified by vendors.

Still, even an approximate or idealized lab result for power consumption of storage systems would be an improvement over the tools avialable to reliably spec power consumption, increasingly a key cost factor for data centers that users in economically strapped times are looking to cut.


Speaking of cutting costs, Serial Attached SCSI (SAS) devices are widely regarded as the cheaper choice of the future to replace Fibre Channel systems. With 6 Gbps SAS products now beginning to ship, the SCSI Trade Association laid out its roadmap for the future of connectivity between Serial Attached SCSI drives and other elements of the infrastructure.

3 Gbps SAS devices connected via InfiniBand connectors; the Mini-SAS HD connector will be used with most 6 Gbps devices. The new roadmap laid out this week specifies that the Mini-SAS HD connector will be the hardware of choice going forward for all types of connectivity into SAS devices.

Why do you care? Because the development plans for the Mini-SAS HD connector going forward will allow it to serve optical, active and passive copper cables with one connector device, and automatically detect the type of cable it’s attached to — meaning that by the time 12 Gbps SAS rolls around, less hardware wil need to be ripped and replaced to support it. Another thing the connector will support in the future is managed connections, meaning a tiny bit of memory in the connector itself that allows the devices to be queried for reporting and monitoring.

The ability to connect SAS devices over optical and active copper cables is a pretty big deal — cable length and expandability limitations have improved significantly with SAS-2, but native cable lengths currently remain limited to 10 meters. While this is already making data center SAS subsystems a reality, it will need more robust connectivity attributes to compete directly with Fibre Channel. Optical cables can stretch as far as 100 meters, and active copper (so called because it contains transcievers that boost signals) to 20 meters.

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