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Supported Functions

• Architecture: Intel-compatible x86, x86_64
• Operating System: Linux kernel 2.6.11~2.6.22
• Basic operations via standard system calls on Linux
• Snapshots
  • Automatically and continuously taken, you can retrieve past state of NILFS filesystem
  • Simultaneously mountable
  • Mountable as read-only file systems via the check point block number
• Simple roll-backing and roll-forwarding in the mounting phase if the file system was not unmounted cleanly

TODO List

The following items are remains.

• Supporting block sizes smaller than the page size (e.g. 1KB or 2KB for the i386 architecture).
• Better error handling.
  -- improved on NILFS 1.0.10. (Jul 18, 2006)
• Sophisticated file system interface.
• Snapshot management mechanism.
• Basic administration tools such as fsck.
• O_DIRECT support.
  -- Direct I/O read was implemented on NILFS 1.0.5; direct I/O write is falled back to the buffered write at present. (Jan 30, 2006)
• Efficient synchronous write operations including fsync(), open() with O_SYNC, and so on.
• mmap() support.
  -- mmap read and write were implemented on NILFS 1.0.9. (May 23, 2006)
• An extended attribute support.
• Quota support.
• atime support.
• Filesystem label support.
• Strict BIO order with a barrier option; ensure the checkpoint blocks and the segusage blocks will be written to the disk in correct order.
  -- Implemented experimentally on NILFS 1.0.4 (Jan 18, 2006)
  -- Turned on the barrier mount option by default on NILFS 1.0.10 (Jul 18, 2006)
• Redundant mechanism for critically important blocks (the super block and the segusage blocks).
• B-tree base directory management.
• More sophisticated B-tree node block management.
• Fixing identified bugs (to be described).
• Testing on the other architectures.
  - Under testing on x86_64 and ppc64 on NILFS 1.0.14 (Oct 25, 2006)
• Performance tuning (e.g. read ahead).
• Source code cleanup.
• Documentation.
  -- A few documents are included on NILFS 1.0.4 (Jan 18, 2006)

Known Problems

Following is a list of issues that have been identified. These will be solved in the future version of NILFS.

• The df command displays the wrong amount of disk space available on the NILFS file system.
• ...

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Last update: Oct 22, 2007