A hybrid approach to nand-flash-based solid-state disks

Li-Pin Chang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

Replacing power-hungry disks with NAND-flash-based solid-state disks (SSDs) is a recently emerging trend in flash-memory applications. One important SSD design issue is achieving a good balance between cost, performance, and lifetime. This study introduces a hybrid approach to large SSDs that combines MLC NAND flash and SLC NAND flash. Each of these flash architectures has its own drawbacks and benefits, and this study proposes that the two can complement each other. However, there are technical challenges pertaining to data placement, data migration, and wear leveling in heterogeneous NAND flash. The experimental results of our study show that combining 256 MB SLC flash with 20 GB MLC flash produces a hybrid SSD. This hybrid SSD is 1.8 times faster than a purely MLC-flash-based SSD in terms of average response time and improves energy consumption by 46 percent. The proposed hybrid SSD costs only four percent more than a purely MLC-flash-based SSD. The extra cost of a hybrid SSD is very limited and rewarding.

Original languageEnglish
Article number5383350
Pages (from-to)1337-1349
Number of pages13
JournalIEEE Transactions on Computers
Volume59
Issue number10
DOIs
StatePublished - 8 Sep 2010

Keywords

  • file systems
  • Flash memory
  • solid-state disks
  • storage systems

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