BLF: an efficient flash translation layer scheme for flash-based storage systems

摘要

The performance of flash memory is limited by its erase-before-write, and erase operations can only be performed in a much larger unit than write operations. To address these problems, we propose an efficient flash translation layer scheme called BLF: Block List Flash Translation Layer. BLF unites log blocks and physical blocks for servicing update requests. It can avoid uneven erasing and low block utilization. The address translation table of BLF can avoid storing an extra internal mapping table. BLF's garbage collection method divides the storage zone into three levels: the active zone where hot data are stored, the inactive zone where cold data are stored, and the transitional zone where reclamation block is stored. If invalid blocks can be reclaimed properly and intensively, merging log blocks with physical blocks can be avoided and the amount of operations can be reduced. Finally, we implement an accurate flash simulator to evaluate the efficacy of BLF and compare it with other flash schemes, demonstrating that the improved performance resulting from BLF substantially outperforms other flash schemes.