PWL: A Progressive Wear Leveling to Minimize Data Migration Overheads for NAND Flash Devices
Fu-Hsin Chen1,a, Ming-Chang Yang2,3,c, Yuan-Hao Chang3,d and Tei-Wei Kuo1,2,3,4,b
1Department of Computer Science and Information Engineering, National Taiwan University, Taiwan (R.O.C.).
2Graduate Institute of Networking and Multimedia, National Taiwan University, Taiwan (R.O.C.).
3Institute of Information Science, Academia Sinica, Taiwan (R.O.C.).
4Research Center for Information Technology Innovation, Academia Sinica, Taiwan (R.O.C.)
As the endurance of flash memory keeps dete- riorating, exploiting wear leveling techniques to improve the lifetime/endurance of flash memory has become a critical issue in the design of flash storage devices. In contrast to existing wear-leveling techniques that aggressively distributes the erases to all flash blocks by a fixed threshold, we propose a progressive wear leveling design to perform wear leveling in a “progressive” way to prevent any block from being worn out prematurely, and thereby to ultimately minimize the performance overheads caused by the unnecessary data migration. The results reveal that, instead of sacrificing the device lifetime, performing wear leveling in such a progressive way can not only minimize the performance overheads but even have potentials to extend the device lifespan.
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