Leveraging Value Locality in Optimizing NAND Flash-Based SSDs
NAND flash-based Solid-State Drives (SSDs) are increasingly being deployed in storage systems at different levels such as buffer-caches and even secondary storage. However, the poor reliability and performance offered by these SSDs for write-intensive workloads continues to be their key shortcoming. Several solutions based on traditionally popular notions of temporal and spatial locality help reduce write traffic for SSDs. However, another form of locality - value locality - has remained completely unexplored. Value locality implies that certain data items (i.e., "Values," not just logical addresses) are likely to be accessed preferentially. Given evidence for the presence of significant value locality in real-world workloads, the authors design CA-SSD which employs Content-Addressable Storage (CAS) to exploit such locality.