tldr/pages/linux/btrfs-filesystem.md

btrfs filesystem

Manage btrfs filesystems. More information: https://btrfs.readthedocs.io/en/latest/btrfs-filesystem.html.

• Show filesystem usage (optionally run as root to show detailed information):

btrfs {{[f|filesystem]}} {{[u|usage]}} {{path/to/btrfs_mount}}

• Show usage by individual devices:

sudo btrfs {{[f|filesystem]}} {{[sh|show]}} {{path/to/btrfs_mount}}

• Defragment a single file on a btrfs filesystem (avoid while a deduplication agent is running):

sudo btrfs {{[f|filesystem]}} {{[de|defragment]}} {{[-v|--verbose]}} {{path/to/file}}

• Defragment a directory recursively (does not cross subvolume boundaries):

sudo btrfs {{[f|filesystem]}} {{[de|defragment]}} {{[-v|--verbose]}} -r {{path/to/directory}}

• Force syncing unwritten data blocks to disk(s):

sudo btrfs {{[f|filesystem]}} {{[sy|sync]}} {{path/to/btrfs_mount}}

• Summarize disk usage for the files in a directory recursively:

sudo btrfs {{[f|filesystem]}} du {{[-s|--summarize]}} {{path/to/directory}}

• Create a swap file:

sudo btrfs {{[f|filesystem]}} {{[m|mkswapfile]}} --size {{8g}} --uuid {{clear|random|time|UUID_value}} {{path/to/swapfile}}