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Isolation: Inexpensively separating cold data via garbage collection to improve the lifetime and performance of NAND flash SSDs
Author(s) -
Zhou Bin,
Wan Shenggang,
Xie Changsheng
Publication year - 2019
Publication title -
concurrency and computation: practice and experience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.309
H-Index - 67
eISSN - 1532-0634
pISSN - 1532-0626
DOI - 10.1002/cpe.5460
Subject(s) - garbage collection , isolation (microbiology) , computer science , nand gate , garbage , flash (photography) , trace (psycholinguistics) , data collection , database , parallel computing , algorithm , programming language , mathematics , logic gate , statistics , art , linguistics , philosophy , microbiology and biotechnology , visual arts , biology
Summary An effective way to mitigate the lifetime and performance problems of NAND flash SSDs induced by garbage collection is separating the cold data and hot data. However, all existing solutions do this separation from the viewpoint of the hot data and thus suffer from expensive cost on monitoring the update behaviors of workloads. Different from the conventional wisdom, we propose to do the separation from the viewpoint of the cold data, which is rooted on the following two dedicated observations. First, the data migrated by garbage collection demonstrate a cold property compared with the other data. Second, it is inexpensive to separate the former data from the latter data. In the proposed method, named Isolation , we i nexpensively s eparate the c ol d d a ta via garbage collec tion . More specifically, through writing the data migrated by garbage collection (cold data) to dedicated blocks and writing the other data (hot data) to other blocks, the separation is done naturally. To evaluate Isolation , we conduct extensive trace‐driven simulations under seven typical workloads. The simulation results demonstrate the effectiveness and efficiency of Isolation . In most cases, Isolation can reduce the number of erasures and average I/O response time up to 47.3% and 80.1%, respectively. Existing approaches integrated with Isolation can further reduce the number of erasures and average I/O response time up to 7.8%‐18.5% and 10.7%‐41.4%, respectively.