Improving the Sustainability of Solid-State Drives by Prolonging Lifetime

In the big data era, vast amounts of data are processed and stored in cloud data centers using Solid-State Drives (SSDs). While SSDs are crucial for efficient data handling as the fast-tier in tiered storage, they also contribute significantly to embodied carbon emissions. In this paper, we explore a method to enhance SSD sustainability by reducing the maximum threshold voltage of flash cells, extending lifespan and improving write performance. However, this leads to decreased read performance due to a high Raw Bit Error Rate (RBER). To improve the SSD performance while prolonging its lifespan, we partition the device into two regions. One region maintains standard voltage levels to efficiently manage read-intensive tasks. The other with a reduced threshold voltage absorbs write-intensive data, leveraging the benefits of extended lifespan and enhanced write performance provided by low-voltage operation. Additionally, we propose a dynamic caching policy that caches frequently accessed data to the DRAM in SSD. Finally, our experimental results demonstrate that the proposed design improves the SSD lifespan by 8.7% to 20.3% compared to some previously proposed schemes while achieving average latency reductions ranging from 19.7% to 69.8%. Our work demonstrates the potential for enhancing the sustainability of SSDs while ensuring high performance, contributing to the reduction of the carbon footprint associated with storage systems in the era of big data.