A Space Reuse Strategy for Flash Translation Layers in SLC NAND Flash Memory Storage Systems
A Space Reuse Strategy for Flash Translation Layers in SLC NAND Flash Memory Storage Systems
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DOI：
10.1109/tvlsi.2011.2142015
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发表时间：
2012-06-01
影响因子：
2.8
通讯作者：
Guan, Yong
中科院分区：
文献类型：
--
作者：
Liu, Duo;Wang, Yi;Guan, Yong
提出了SLC NAND闪存存储系统中闪存转换层的空间复用策略。其基本思想是防止具有许多空闲页的块在合并操作中被擦除。保留的块作为替换块进一步重用。通过这种方式，提高了NAND闪存中每个块的空间利用率和擦除计数数。为了提高单级单元（SLC） NAND闪存的续存性和空间利用率，我们提出了一种可复用的闪存转换层（FTL），称为可复用NFTL （RNFTL）。对频繁更新操作和顺序写操作下的RNFTL进行了性能分析，并与典型的FTL方案进行了理论比较。我们还讨论了在基于日志块的FTL方案中应用重用策略的机会。据我们所知，这是第一次在超光速中采用空间重用策略来提高NAND闪存的空间利用率和耐用性。实验是在日常工作负荷中采集的一组痕迹上进行的。结果表明，该空间复用策略能有效提高空间利用率、块寿命和磨损均衡性。
This paper presents a space reuse strategy for flash translation layers in SLC NAND flash storage systems. The basic idea is to prevent a block with many free pages from being erased in a merge operation. The preserved blocks are further reused as replacement blocks. In such a way, the space utilization and the number of erase counts of each block in a NAND flash are enhanced. By employing the reuse strategy, we propose a reuse-aware flash translation layer (FTL) called reuse-aware NFTL (RNFTL) to improve the endurance and space utilization of single level cell (SLC) NAND flash. We provide the performance analysis of RNFTL for frequent update operations and sequential write operations, and theoretically compare RNFTL with representative FTL schemes. We also discuss the opportunity to apply the reuse strategy in log-block-based FTL schemes. To the best of our knowledge, this is the first work to employ a space reuse strategy in FTLs to improve the space utilization and endurance of NAND flash. The experiments have been conducted on a set of traces collected from real workload in daily life. The results show that the space reuse strategy can effectively improve space utilization, block lifetime and wear-leveling compared with the previous work.