Design And Analysis Of Reliable Energy-efficient Parallel Storage Systems

In terms of modern data centers,it's no longer the only target to improve the performance of parallel file systems.Because of the unpreventable problems about energy consumption and reliability,it's a demanding and challenging task for large scale storage systems to reduce energy consumption while retaining acceptable system reliability.However,most of traditional energy saving techniques inevitably have adverse impacts on the parallel disk systems.Existing solutions tend to spin up and down hard disk drives(HDDs)or replace HDDs with solid state disks(SSDs).These solutions may cause sever mechanical malfunction of HDDs and lead to permanent data loss.Morever,heavy write I/O loads shorten the lifetime of SSDs due to the limited numbers of erasure cycles of flash memory.In this paper,we propose a reliable energy-efficient Storage System called RESS to address the reliability issues of energy-efficient parallel storage system.RESS aims at improving both energy efficiency and reliability of parallel storage systems by seamlessly integrating HDDs and SSDs.The core of RESS is a transformative middleware layer,which reorganizes the I/O workload for underlying parallel file systems.With the help of the middleware layer,RESS can distribute popular data to SSDs and put HDDs into the low-power mode under light workload conditions without modification of the parallel systems.Under light workload conditions,RESS spins down HDDs into the low-power mode,thereby offering energy conservation.Under heavy loads,energy savings become impossible.In this case,all hard drives are kept active while turning off SSDs to decrease the number of data erasures that seriously affect SSD reliability.In this paper,we introduce a simulation test tool called DiskSim to evaluate RESS.The result of simulation shows RESS can conserve up to 70%energy consumption compared to traditional RAID structure while retaining system reliability.Furthermore,we achieve the real-world implementation of RESS on a cluster and apply real-world test to RESS.The result of experiment shows,RESS achieves better I/O performance compared to traditional RAID structure.