Phoenix: Reviving MLC blocks as SLC to extend NAND flash devices lifetime

On a Multi-Level Cell (MLC) flash memory, a flash block that is becoming unreliable to store multiple bits per cell can be “revived” by storing only a single bit per cell. While the revived-block capacity is halved, its lifetime is significantly extended without jeopardizing the stored data. We present Phoenix, a technique that benefits from this feature to extend a device lifetime, and we evaluate its potential through detailed trace simulation on realistic benchmarks. Phoenix shows systematic lifetime extensions ranging from 3% up to 17%, without extra memory requirements or performance loss.