WARM: Improving NAND flash memory lifetime with write-hotness aware retention management
2015 31st Symposium on Mass Storage Systems and Technologies (MSST)(2015)
摘要
Increased NAND flash memory density has come at the cost of lifetime reductions. Flash lifetime can be extended by relaxing internal data retention time, the duration for which a flash cell correctly holds data. Such relaxation cannot be exposed externally to avoid altering the expected data integrity property of a flash device. Reliability mechanisms, most prominently refresh, restore the duration of data integrity, but greatly reduce the lifetime improvements from retention time relaxation by performing a large number of write operations. We find that retention time relaxation can be achieved more efficiently by exploiting heterogeneity in write-hotness, i.e., the frequency at which each page is written. We propose WARM, a write-hotness aware retention management policy for flash memory, which identifies and physically groups together write-hot data within the flash device, allowing the flash controller to selectively perform retention time relaxation with little cost. When applied alone, WARM improves overall flash lifetime by an average of 3.24× over a conventional management policy without refresh, across a variety of real I/O workload traces. When WARM is applied together with an adaptive refresh mechanism, the average lifetime improves by 12.9×, 1.21× over adaptive refresh alone.
更多查看译文
关键词
WARM,NAND flash memory lifetime,write-hotness aware retention management,NAND flash memory density,internal data retention time relaxation,flash device data integrity property,I/O workload traces,adaptive refresh mechanism
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络