Current Status

Supported Features

• Basic POSIX file system features
• Snapshots
  • Automatically and continuously taken, you can retrieve past state of NILFS file system.
  • No limit on the number of snapshots until the volume gets full
  • Mountable as read-only file systems
  • Mountable concurrently with the writable mount (convenient to make consistent backups during use)
  • Quick listing
  • Easy administration
• Background Garbage Collection
  • Can maintain multiple snapshots
  • Selectable GC Policy, which is given by a userland daemon.
• Quick crash recovery on-mount
• Read-ahead for meta data files as well as data files
• Block sizes smaller than page size (e.g. 1KB or 2KB)
• Redundant super block
• Online resizing (since Linux-3.x and nilfs-utils 2.1)
• FITRIM
• Related utilities (by contribution of Jiro SEKIBA)
  • grub2
  • util-linux (blkid, libblkid, uuid mount)
  • udisks, palimpsest
  • Filesystem label (nilfs-tune)

TODO List

• Deletion of orphan inodes
• O_TMPFILE
• Hole-Punching
• clone_file_range
• in-kernel GC
• Smarter and more efficient Garbage Collector
• fsck
• Extended attribute
• POSIX ACLs
• Tool listing versioning history of a specified file
• Modelated checkpointing: make a checkpoint only when file overwriting/deletion occurs
• nilfs-debug: offline debug tool to analyze broken volume
• Better support of synch operations (fsync, etc).
• Performance improvement (Better Block I/O submission)
• Checkpoint rollback
• Checkpoint based remote replication
• Less frequently updated superblock for flash devices.
• Optimization for silicon disks (e.g. SSD)
• Online defrag
• Faster inode allocation
• atime
• Compression of old data
• Shred file along with its past versions
• Better support of mmap and direct I/O.
• System/package undo tool support: snapper, etc.
• Unified user command ``nilfs'' (rather than separate commands like lscp, rmcp, mkcp, etc).
• Offline resizing
• Writable snapshots
• Quota support
• B-tree based directory management
• Extent support