Adaptive flash translation layer design for spaceborne solid state storage systems

Abstract:

The traditional flash translation layer (FTL) algorithm of spaceborne storage system adopts page-level FTL mapping scheme and fixed partition file management strategy, which has many problems, such as high host occupancy, long system response time, and no consideration of FLASH wear balance. Therefore, a data-driven Adaptive Superblock FTL (DASFTL) algorithm was proposed based on the analysis of the working principle of traditional spaceborne storage system and spaceborne solid state storage system. DASFTL adopts the hierarchical address mapping scheme of adaptive superblock, in which the super block mapping table is the first level mapping and the page mapping table is the second level mapping for improving response time. The superblock was taken as the smallest unit of FLASH address management to reduce the dependence of storage system on host. Dynamic block recovery weight was introduced as the criterion of superblock grouping and target recovery block selection to balance the wear degree of the physical blocks in FLASH chip and prolong its service life. In the end, a hardware test platform was built to verify the DASFTL algorithm. Results show that compared with the traditional spaceborne FTL algorithm, the host occupancy rate and the system response time of the DASFTL algorithm were increased by 51.7% and 46.1%, respectively. The balanced wear performance of the FLASH chip was significantly improved, which can prolong the service life of the FLASH chip.