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A real-time dependable flash storage system

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journal contribution
posted on 22.05.2020 by Alistair McEwan, Muhammed Komsul
One of the limitations of flash memory in real time, high dependability systems is its need for garbage collection and the resulting performance degradation due to non-deterministic response times. Recent work has presented RAID architectures for solid state storage systems. These RAID architectures increase the dependability from a data storage perspective but they do not provide application level dependability when real-time response times are required. In this study we present a garbage collection aware flash translation layer that offers guaranteed access time to a solid state RAID array by managing incoming requests and preventing them from being blocked by ongoing garbage collection. We present a novel serial technique with a dynamic page allocation mechanism that completely eliminates non deterministic behaviors of the garbage collectors in the array. The result is real-time access guarantees that maintain the data dependability enhancements using a run time parity migration technique. The mechanisms are evaluated using trace driven simulator and a number of synthetic and realistic traces. Simulation results indicate that the garbage collection aware techniques offer improved upper bound response times for I/O requests of up to 73% compared to an existing mechanism, without disturbing the data dependability at the storage level. Traces dominated by random writes exhibit similarly significant enhancements.

Funding

This work was supported by the University of Leicester, U.K.

History

Citation

A. A. McEwan and M. Z. Komsul, "A Real-Time Dependable Flash Storage System," in IEEE Access, vol. 7, pp. 142974-142990, 2019, doi: 10.1109/ACCESS.2019.2944764.

Version

VoR (Version of Record)

Published in

IEEE Transactions on Dependable and Secure Computing

Volume

7

Pagination

142974 - 142990

Publisher

Institute of Electrical and Electronics Engineers

issn

1545-5971

eissn

2169-3536

Acceptance date

23/09/2019

Copyright date

2019

Language

en

Licence

Exports