5.10. File Systems

5.10.1. Ext4 - The default file system

Fedora 11 utilizes ext4 as the default file system. ext4 brings significant new features and performance enhancements including:

Improvements in file systems and sizes
- File system size increased to one exabyte (1 EiB)
- File size limit is sixteen terabytes (16 TiB)
- No limit on number of sub-directories
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- Extents increase performance in certain situations, especially large files
- Multiblock allocation is a new file block allocation method with faster write speed
- These combine with delayed allocation of blocks for better performance and fragmentation

5.10.1.1. Buffered Data Loss Mitigation

The recent news about buffered data loss experienced during a system crash with ext4 has resulted in upstream, and thus F11, flushing file data on a truncate or rename to mitigate this issue.

5.10.1.2. Migration from ext3 to ext4

It is generally recommended that users wishing to make use of ext4 start with a freshly formatted partition. However you may install with the ext4migrate boot option if you wish to convert your legacy ext3 partitions to ext4. Users are cautioned that they will not realize many of the benefits ext4 since the data currently residing on the partition will not make use of extents. New data will make use of extents. Please note that as suggested by the requirement to pass a boot option that migration to ext4 has not been heavily tested and users are urged to backup filesystems before attempting migration

5.10.1.3. No grub support

Currently grub doesn't support booting from an ext4 partition so make sure to utilize ext2/3 for /boot

5.10.2. btrfs - next-generation Linux filesystem

Fedora 11 makes btrfs, the next-generation Linux filesystem available as a technology preview. To enable btrfs pass icantbelieveitsnotbtr as a boot potion. Users are warned that btrfs is still experimental and under heavy development. The on-disk format may yet change and much functionality is still missing such as a fully operative fsck or even proper out-of-space handling.

5.10.2.1. No grub support

Currently grub doesn't support booting from a btrfs partition so make sure to utilize ext2/3 for /boot