Modeling the Endurance Reliability of Intradisk RAID Solutions for Mid-1X TLC NAND Flash Solid-State Drives

Ensuring data protection in solid state drives (SSDs) is vital in enterprise application scenario. However, as the reliability of their storage medium, namely, the NAND Flash, is decreasing at the same pace of the technology scaling, this activity is becoming nontrivial. The evaluation of different recovery strategies that employ complex error-correction codes and second-level error correction is becoming a de facto. In this paper, we model the endurance reliability of an advanced data protection methodology like the intradisk redundant array of independent disks (RAIDs) applied on mid-1X triple level cell NAND Flash-based SSD. The performed investigations include a parametric analysis of the uncorrectable bit-error rate. By developing a dedicated discrete-time Markov-chain model of an SSD, we evidenced that intradisk RAID5 and RAID6 allow achieving an inherent reliability level compliant with the qualification target for enterprise SSD. Finally, we provide a global picture of the disk economy when intradisk RAID is implemented.