MAID 2.0 technology and disk spin down can help users accomplish effective green storage practices, allowing them to reduce the data footprint of their data storage infrastructure and cut their power costs.
In this SearchStorage.co.UK podcast interview, Ian Lock, storage practice lead at GlassHouse Technologies (UK), discusses MAID 2.0 and disk spin down. Lock covers the benefits of MAID and disk spin down, as well as the best use cases and limitations of these green storage technologies.
You can read a transcript of the interview below or listen to it in its entirety as an MP3.
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Achieving green storage with disk spindown and MAID technologies
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SearchStorage.co.UK: What is MAID and what is disk spin down?
Lock: MAID stands for massive array of idle disks, and is a technology used in large disk subsystems where disk drives not in active use at any given time are automatically switched off to save power. MAID systems work by spinning down drives which have not been used to service read or write requests for a given time.
As disk drives consume 80% of the power in large arrays, this has the potential to reduce power and cooling costs greatly. The reduced energy consumption and heat output mean that MAID systems can pack drives into drive enclosures much more densely than in standard arrays.
MAID systems usually use SATA drives that are lower in cost than Fibre Channel (FC) disks, but with lower raw performance levels. In MAID systems, these lower performance levels at the disk are not so critical as the data stored on them should not demand the highest levels of performance.
In its first incarnation, MAID 1.0, each drive in a MAID system was either fully powered up or spinning, or fully off and not spinning at all. This approach was able to achieve significant power savings but had a dramatic negative effect on performance as spin-up times for some drives could be measured in tens of seconds. This I/O delay is impractical for most applications and doubts over its usability stopped many potential buyers from putting such systems into production.
MAID 2.0 increases usability by adding multiple modes of operation instead of the binary on/off approach of MAID 1.0. Drives can be in one of four states: In state 1, drives are fully on and spinning; in state 2, drive heads are unloaded; in state 3, disk platters spin at a lower rotation rate;, and in state 4 drives are put into sleep mode where they aren't spinning at all. MAID 2.0 products can reduce response times over MAID 1.0 by as much as 75% while still giving substantial energy and cost savings.
While MAID is the name coined for the overall concept, spin down is the feature of controlling the disk drives within the array. Spin down is the term used by some of the larger storage vendors to describe how they have incorporated this into some of their midrange array of MAID products.