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Data Loss in RAID-5 Storage Systems with Latent Errors

Authors:
Ilias Iliadis

Keywords: Storage; Reliability; Data placement; MTTDL; EAFDL; RAID; MDS codes; Information Dispersal Algorithm; Prioritized rebuild; Repair bandwidth; Network bandwidth constraint.

Abstract:
Storage systems employ redundancy and recovering schemes to protect against device failures and latent sector errors and enhance reliability. The effectiveness of these schemes has been evaluated based on the Mean Time to Data Loss (MTTDL) and the Expected Annual Fraction of Data Loss (EAFDL) metrics. The reliability degradation due to device failures has been assessed in terms of both these metrics, but the adverse effect of latent errors has been assessed only in terms of the MTTDL metric. This article addresses the issue of evaluating the amount of data losses caused by latent errors. It presents a methodology for obtaining MTTDL and EAFDL of RAID-5 systems analytically in the presence of unrecoverable or latent errors. A theoretical model capturing the effect of independent latent errors and device failures is developed, and closed-form expressions are derived for the metrics of interest.

Pages: 1 to 9

Copyright: Copyright (c) IARIA, 2019

Publication date: March 24, 2019

Published in: conference

ISSN: 2308-4022

ISBN: 978-1-61208-699-6

Location: Valencia, Spain

Dates: from March 24, 2019 to March 28, 2019