Flash Storage Systems

Software Managed Flash: Re-architect the Flash Storage System

TxSSD: Efficient Transactions on Flash-based SSDs

In-Memory Storage

Transactional Persistent Memory: Crash Consistency in Persistent Memory

Persistent Memory File Systems

Distributed Persistent Memory

Software Managed Flash: Re-architect the Flash Storage System

(a.k.a., Software Defined Flash, Open-Channel SSD, Application Managed Flash)

Hard Disk Drive (HDD) has been the donimating storage device since 1950s (almost from the birth of electronic computers). With the popularity of flash-based SSDs, we need to rethink both the storage architecture and the software design philosophy of flash storage. Since 2010, we proposed to directly manage flash memory via software (a.k.a., Open-Channel SSD) [FAST'13, DATE'14, USENIX ATC'16], redesign the file system [FAST'13, FAST'14, USENIX ATC'16] and the key-value store [CODES+ISSS'17], and re-investigate into the distributed storage designs [SC'17, ...]. Milestones in this project:

  1. 2011.10: Ph.D Thesis Proposal
  2. 2012.12: SATA Raw Flash Device customized from a commercial company
  3. 2013.2: OFSS (FAST‘13) paper publised: (1)the Software-Manage Flash architecture on Raw Flash Device (Open-Channel SSD) to enable software-hardware co-design (e.g., Object-based Flash Storage System); (2) endurance-aware software design on flash storage
  4. 2013.11: PCIe Raw Flash Device (Open-Channel SSD) customized from a commercial company
  5. 2014.2: ReconFS (FAST'14) paper published: a novel file system namespace management with a separated volatile and persistent directory tree, which rebalances the normal metadata update cost and recovery overhead leveraging the asymmetric read-write performance of flash SSDs
  6. 2015.1: Invitated paper published in Communications of KIISE: rethink the design of flash file systems.
  7. 2016.6: ParaFS (USENIX ATC'16) paper published
  8. 2017.10: FlashKV (CODESS+ISSS'17) paper published
  9. 2017.12: Open-Channel Storage System has been released, including local file system, key-value store, distributed object store, and distributed file system. All these systems are built on top of open-channel SSDs.

Related Papers

  1. Youyou Lu, Jiwu Shu, Weimin Zheng,
    Extending the Lifetime of Flash-based Storage through Reducing Write Amplification from File Systems,
    in Proceedings of the 11th USENIX Conference on File and Storage Technologies (FAST'13), February 12-15, 2013, San Jose, USA

    The first paper to re-architect the flash storage stack to directly manage flash via software. It removes the FTL from the SSD and introduces the Raw Flash Device (Open-Channel SSD).

  2. Youyou Lu, Jiwu Shu, Wei Wang,
    ReconFS: A Reconstructable File System on Flash Storage,
    in Proceedings of the 12th USENIX Conference on File and Storage Technologies (FAST'14), February 17-20, 2014, Santa Clara, USA

  3. Jiacheng Zhang, Jiwu Shu, Youyou Lu
    ParaFS: A Log-Structured File System to Exploit the Internal Parallelism of Flash Devices,
    in Proceedings of the USENIX Annual Technical Conference (USENIX ATC'16), June 22-24, 2016, Denver, CO

  4. Jiacheng Zhang, Youyou Lu, Jiwu Shu, Xiongjun Qin
    FlashKV: Accelerating KV Performance with Open-Channel SSDs,
    presented at (CODESS+ISSS'17), Oct 2017, Korea, published in ACM Transactions on Embedded Computing Systems

  5. Youyou Lu, Jiacheng Zhang, Jiwu Shu,
    Rethinking the File System Design on Flash-based Storage,
    Communications of the Korean Institute of Information Scientists and Engineers (KIISE), 2015
    (Invited Paper)

  6. Youyou Lu, Jiwu Shu,
    A Survey on Flash-based Storage Systems,
    Journal of Computer Research and Development, Vol 50(1), 2013 (in Chinese)