Exploiting Compression-Induced Internal Fragmentation for Power-Off Recovery in SSD

Dongwook Kim, Youjip Won, Jaehyuk Cha, Sungroh Yoon, Jongmoo Choi, Sooyong Kang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Recovery from sudden power-off (SPO) is one of the primary concerns among practitioners which bars the quick and wide deployment of flash storage devices. In this work, we propose Metadata Embedded Write (MEW), a novel scheme for handling the sudden power-off recovery in modern flash storage devices. Given that a large fraction of commercial SSDs employ compression technology, MEW exploits the compression-induced internal fragmentation in the data area to store rich metadata for fast and complete recovery. MEW consists of (i) a metadata embedding scheme to harbor SSD metadata in a physical page together with multiple compressed logical pages, (ii) an allocation chain based fast recovery scheme, and (iii) a light-weight metadata logging scheme which enables MEW to maintain the metadata for incompressible data, too. We performed extensive experiments to examine the performance of MEW. The performance overhead of MEW is 3 percent in the worst case, in terms of the write amplification factor, compared to the pure compression-based FTL that does not have any recovery scheme.

Original languageEnglish
Article number7172998
Pages (from-to)1720-1733
Number of pages14
JournalIEEE Transactions on Computers
Issue number6
Publication statusPublished - 1 Jun 2016
Externally publishedYes


  • compression
  • flash translation layer
  • power-off recovery
  • Solid-state drives


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