COPR: a cost-oriented recycling policy for flash translation layer

A coarse-grained log block allocation policy has been proved to be efficient in the newly emerging blockgroup- based NAND flash translation layers (FTL). However, these FTL schemes can result in a large garbage collection overhead in terms of valid page copy and erase operations, because they employ a least recently used (LRU) algorithm as their victim selection policy for garbage collection. In this paper, we propose a cost-oriented recycling policy (CORP) to remedy this problem, where the victim block-groups for garbage collection are selected based on the recycling operation overhead and the write access possibility of each logical block. Trace-driven simulations show that the proposed scheme greatly reduces the garbage collection overhead and promises a more efficient FTL solution.