Tiler: An Autonomous Region-Based Scheme for SMR Storage

Shingled Magnetic Recording (SMR) Disks are adopted as a high-density, non-volatile media that significantly precedes conventional disks in both the storage capacity and cost. However, inefficient read-modify-writes (RMWs) greatly challenge the management of SMR disks. This article for the first time presents an approach called Tiler to manage SMR disks by dividing the physical space into small autonomous regions (ARs). Each AR can manage its space allocation, address mapping, and cleaning independently. By managing these ARs in a log-structured way, RMWs can be avoided; besides, ARs can also help update data when the adjacent tracks contain no valid data. Tiler is capable of partitioning a large-scale cleaning into self-contained-small-scale cleaning and thus, the data that need to be relocated are limited inside independent ARs, which further minimizes the performance overhead. Our experimental results show that Tiler can shorten the overall system response time by 50.21 percent and reduce the cleaning time by 90.24 percent on average.