基于日志结构的闪存均衡回收策略

Log-structured even recycle strategy for flash storage

针对闪存存储的异址更新和有限擦除等特点以及由此引起的使用寿命优化问题,提出基于日志结构的资深块优先回收(SBFR)策略.为了有效地提高使用寿命,闪存存储管理必须在减少垃圾回收开销的同时实现闪存的均衡擦除,并尽量避免两者的冲突.SBFR采用回收和聚集分散的冷数据的方法,选择块利用率和资历等级作为标准来判定冷数据和筛选回收块,高效集成了一种强制均衡策略.实验结果表明,SBFR能够减少回收开销和实现理想的均衡效果,有效地提高闪存存储的使用寿命.

Some factors, like out-of-place write and limited erasure lifecycles, pose reliability challenge for flash storage. A novel recycle scheme, called senior-block-first recycle method （SBFR）, was proposed for log-structured flash management in order to mitigate the problem. In order to extend the functional life- time, the flash management must utilize blocks evenly and lower space-reclamation overhead at the same time, and has to avoid the confliction of these two objectives. SBFR tended to collect and assemble scat- tered cold data. Utilization-ratio and seniority-degree were taken as the selection criterions for block recy- cle. A forced wear-leveling mechanism was incorporated into the recycle method with little overhead. Ex- perimental results indicate that SBFR method can effectively prolong flash＇s functional life-time by leveling erase counts of all blocks evenly with small recycle overhead.