CacheFS

A FUSE file system that caches remote files.

Open -> lookup file -> fetch into cache -> local operations

'cfstool flush' to push changes to the server

Run

make run

The fuse driver takes parameters like the mount command. python direct.py /Users/sb/cachefs/back/ /Users/sb/cachefs/front/

Run tests

All test can be triggered by a make command

make tests (runs all tests) make testfileops (runs basic file tests non-fuse directory) make testfrontend (tests file tests on the cachefs frontend directory)

TODO: backend (rsync)

make test Add -s to disable capturing (print() will be shown)

Design

/front Contains the virtual view using cache and backend /cache Contains the medata /back Way to access the data on the server

Server

• Read config file
• Cache pools (pinned/LRU)
• Start FUSE driver

Fuse

• File operations
  • open
  • close
  • read
  • write

Cache

Store the cached files somewhere locally. Called from within the FUSE driver.

• open (bring in the file)
• read (look in cache)
• wirte (write through to server)
• close (v2 sync out)

Cache is organized in pools (LRU, pinned)?

Syncer

Keep log of modified files. Push them via the backend to the server if avialable.

Backend

Abstract away different forms to access the files on the server e.g. cp, rsync, SSHFS, SMB, AFP, ssh, ftp

• Interface
  • list files (pathname)
  • get (pathname, offset, size)
  • push (pathname, offset, size)
  • disconnect (flush all changes out)

Cmdline Tools

• status, utilization
• pin files
• fetch files
• push/synch back to origin

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-- -- Implementation

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Class: Directory

• Root directory is mountpoint of front
• Contains list of Files

Class: File

• Cached?
• Location where stored in cache
• Location where stored in back
• Attributes, Size
• List of chunks

Class: Chunk

• File, base
• offset, size
• dirty
• pool

Class: Cache

• List of pools (pinned, LRU)
• Container for files
• Keep log of modified chunks
• Sync operation to flush changes to server

Class: Backend

Wrapps file operations to the server, supports multiple protocols

• ls-directory (pathname) ?
• ls-file (pathname) ?
• get (pathname, offset, size)
• push (pathname, offset, size)