1 / 21

Distributed File Systems

Distributed File Systems . Madhu K. Jayaprakash. Papers Reviewed . [1] A Low-bandwidth Network File System: A. Muthitacharoen, B. Chen, and D. Mazieres [2] Ivy: A Read/Write Peer-to-Peer File System: A. Muthitacharoen, R. Morris, T.M. Gil, B. Chen. [1] - Purpose.

dea
Download Presentation

Distributed File Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Distributed File Systems Madhu K. Jayaprakash

  2. Papers Reviewed • [1] A Low-bandwidth Network File System: A. Muthitacharoen, B. Chen, and D. Mazieres • [2] Ivy: A Read/Write Peer-to-Peer File System: A. Muthitacharoen, R. Morris, T.M. Gil, B. Chen

  3. [1] - Purpose • Existing Network File Systems are bandwidth intensive • Alternatives to Network File Systems • Make and update local copies • Update Conflicts • Remote login and edit files • Latency throttles interactivity • Make the file system more efficient!

  4. [1] – Strategy • Reduce amount of data sent between Client and Server • Large Persistent File Cache on Client • File Leases • Exploit Cross file similarities

  5. Design • Break files into Chunks • Index Chunks by their Hash on Client and Server, Store in a Cache • Transfer Chunks only when needed • Maintain leases

  6. [1] – File Read

  7. [1] – File Write

  8. [1] – Evaluation: Cross File Similarities

  9. [1] – Evaluation: Bandwidth Utilization

  10. [1] – Evaluation: Latency

  11. Conclusion • Corner cases do exist that diminish performance • Bandwidth can be reduced through • Client Caching • File Leases • Exploiting Cross-File similarities

  12. [2] - Purpose • Remove Central Server • Single Point of failure • Bottleneck • Increase availability

  13. [2] – Strategy • Small Network of Peers • Distribute data among Peers • Scan Peers to find needed information

  14. [2] - Design • Log maintained at each host • Writes touch local log • Reads require all logs • All data stored in DHash

  15. [2] - DHash • Peer-to-Peer Block Storage System • Distributes and Replicates blocks (Handles communication) • “Black-box” to Ivy

  16. [2] - Log • Linked list of Records • Record contains single file system modification • Client maintains pointer to most recent record • Scan actions in logs to build file

  17. [2] - Snapshots • Performance optimization • Collect log information from Group members • Scan them to create a snapshot of entire File System • Store in DHash • Control malicious attacks through Group membership

  18. [2] - Consistency • File Close-to-Open • Conflicts – No Locking • Concurrent access • Network Partitions • Tools provided to reconcile

  19. [2] - Evaluation • Modified Andrew Benchmark • Create Directory Tree • Copy files into directories • Walk the directory tree while reading the attributes of each file • Read the files • Compile the files into a program

  20. Conclusion • Interesting concept • No Central Server • Supports Concurrency/Partitioning without locks • No Trust required • Concerns • Dependency on DHash servers • Size of Logs • Performs two to three times slower than NFS

  21. Related Works • DHash • FreeNet • FarSite

More Related