A method to vary the Host interface signaling speeds in a Storage Array driving towards Greener Storage

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Publish Date: 
Wednesday, September 21, 2011
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Abstract: 

This paper describes a method which we can effectively alter the signaling speeds of a Host Interface based on set performance criterion or user defined time of day criterion that are user definable. The end goals are considerable power savings by changing the signaling speeds to a lower supported speed as our background study indicates the same .Bringing down the MTBF of the components by operating them at nominal speeds and improving the operable life span of the system move towards Greener Storage, low power operation, minimize Heat dissipation and emission reduction. We are also achieving demand based Host interface bandwidth allocation to balance the throughput requirements of the application.

Learning Objectives

Problems and scope of the analysis and investigation ( Power Consumption differences, Power Bandwidth Ratio, Raw Data rate and Effective data rate)
How does the method of this paper make the optimal use of the available raw bandwidth by switching to lesser raw bandwidth if the data rate doesn’t utilize the initial higher bandwidth rate on offer?
How are the performance thresholds defined based on the specified performance metrics capable of the array?
How does the method of this paper proposal will deliver considerable power savings even when the system is active and performing IOs? (Link Speed Decison Change and Decison Logic)
How does the method of this paper address exception conditions and allows rollback to the last supported speed if the system can’t perform a link speed change?