1 / 18

Optimizing Disk I/Os in Hierarchical File System Design

Explore efficient file system design strategies for improved disk I/O operations, considering infinite resources like CPUs, memory, disk storage, and network bandwidth. Learn about different file system components and their optimization. Design considerations for large and small file systems, memory and disk capacity matching, and resource-efficient approaches are discussed.

velma
Download Presentation

Optimizing Disk I/Os in Hierarchical File System Design

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. Homework 9 Sarah Diesburg Operating Systems COP 4610

  2. / Hierarchical Name Space • To access the data content of /pets/cat.jpg • The system needs to perform the following disk I/Os 1. Read in the file header for the root directory ‘/’ • Stored at a fixed location on disk

  3. / Hierarchical Name Space • To access the data content of /pets/cat.jpg • The system needs to perform the following disk I/Os 2. Read the first data block for the root directory • Lookup the directory entry for pets pets

  4. / Hierarchical Name Space • To access the data content of /pets/cat.jpg • The system needs to perform the following disk I/Os 3. Read the file header for pets pets pets

  5. / Hierarchical Name Space • To access the data content of /pets/cat.jpg • The system needs to perform the following disk I/Os 4. Read the first data block for the pet directory • Lookup the directory entry for cat.jpg pets pets cat

  6. / Hierarchical Name Space • To access the data content of /pets/cat.jpg • The system needs to perform the following disk I/Os 5. Read the file header for cat.jpg pets cat pets cat

  7. / Hierarchical Name Space • To access the data content of /pets/cat.jpg • The system needs to perform the following disk I/Os 6. Read the data block for cat.jpg pets cat pets cat

  8. Hierarchical Name Space • So how many disk I/Os do we need to resolve the path? • Depends what resolving means • 5 to resolve the path (everything but reading the file) • 6 if resolving includes reading the first file data block

  9. How would you design your file system differently? • If you have infinite number of CPUs? • If you have infinite memory size? • If you have infinite disk storage? • If you have infinite network bandwidth?

  10. File System Components • Disk layout • Naming • Protection • Reliability

  11. Infinite Number of CPUs • Some of you forgot to think about disk seek and data transfer times • These are separate from computational power • Use naming schemes that take a lot of computational power • E.g., relational, contextual, content-based • Hash data block locations • Maybe encryption for extra security

  12. Infinite Memory Size • Load (cache) all file to data mappings into memory on boot • Memory-map files to disk

  13. Infinite Disk Storage • Make extra copies for reliability • Make extra copies for speed • Contiguous or segment-based allocation • No longer need to worry about external fragmentation

  14. Infinite Network Bandwidth • Automatic remote copy (remote RAID 1?) • Store metadata locally (accessed more often), store data remotely (accessed less often)

  15. How would you design a file system • for only large files? • for only small files? • if memory capacity == disk capacity

  16. For large files • Multi-level indexed allocation • Hash allocation – change to one block won’t affect rest

  17. For small files • Indexed allocation • Small segmented allocation

  18. Memory capacity = Disk capacity • Cache all metadata and files as they are being used

More Related