Home // CTRQ 2022, The Fifteenth International Conference on Communication Theory, Reliability, and Quality of Service // View article

Effect of Lazy Rebuild on Reliability of Erasure-Coded Storage Systems

Authors:
Ilias Iliadis

Keywords: Storage; Deferred recovery or repair; Unrecoverable or latent sector errors; Reliability analysis; MTTDL; EAFDL; RAID; MDS codes; stochastic modeling.

Abstract:
Erasure-coding redundancy schemes are employed to ensure improved reliability of storage systems against device failures. The effect of the lazy rebuild scheme on the Mean Time to Data Loss (MTTDL) and the Expected Annual Fraction of Data Loss (EAFDL) reliability metrics is evaluated. A theoretical model that considers the effect of latent errors and device failures is developed. Analytical reliability expressions for the symmetric, clustered, and declustered data placement schemes are derived. It is demonstrated that the employment of lazy rebuild results in a reliability degradation of orders of magnitude. Independently of whether lazy rebuild is used, for realistic values of sector error rates, the results obtained demonstrate that MTTDL degrades, whereas EAFDL remains practically unaffected. It is also shown that the declustered data placement scheme offers superior reliability.

Pages: 1 to 10

Copyright: Copyright (c) IARIA, 2022

Publication date: April 24, 2022

Published in: conference

ISSN: 2308-4022

ISBN: 978-1-61208-944-7

Location: Barcelona, Spain

Dates: from April 24, 2022 to April 28, 2022