[NILFS] Version 1 Status

Status of NILFS version 1

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

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)

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.
...

Last update: Oct 22, 2007