A page lifetime-aware scrubbing scheme for improving reliability of Flash-based SSD

Abstract

Solid-state drive (SSD) has gain prevalence in consumer and enterprise storage markets. However, its reliability is declining with the wearing of the Flash memory. The error correcting codes (ECCs) are generally applied in SSD to cope with bit errors caused by abrasion, however, the lifetime of pages in Flash is still limited to their fixed correctability. Due to different process and usage, the pages of Flash deteriorate in different speeds, which limited the service time of SSD. In order to prolong the lifetime of SSD, we proposed a Page Lifetime-aware Scrubbing (LaScrub) scheme to find dangerous pages which exist more bit errors. The simulation results show the proposed scheme is able to enhance the reliability of SSD. It gains 86% storage space compared with normal SSD at the same reliability requirement.