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technology/linux/filesystems/Btrfs.md

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+---
+arch-wiki: https://wiki.archlinux.org/title/Btrfs
+obj: filesystem
+---
+# Btrfs
+Btrfs is a modern copy on write (CoW) filesystem for [Linux](../Linux.md) aimed at implementing advanced features while also focusing on fault tolerance, repair and easy administration. Btrfs is licensed under the GPL and open for contribution from anyone.
+
+## Create the filesystem
+**Single Device**:
+``` shell
+mkfs.btrfs -L _mylabel_ /dev/partition
+```
+**Multiple Devices (similiar to [RAID](RAID.md))**:
+```shell
+mkfs.btrfs -d single -m raid1 /dev/part1 /dev/part2 ...
+```
+
+## Subvolumes
+Subvolumes are their own seperated namespaces and work like [ZFS](ZFS.md) Datasets. They can be mounted seperately. Each Btrfs file system has a top-level subvolume with ID 5.
+
+**Create a subvolume**:
+```shell
+btrfs subvolume create /path/to/subvolume
+```
+
+**List suvolumes**:
+```shell
+btrfs subvolume list -p path
+```
+
+**Delete subvolume**:
+```shell
+btrfs subvolume delete /path/to/subvolume
+```
+
+## Using Swapfiles
+Swapfiles can be used by disabling CoW:
+```shell
+chattr +C /path/to/swapsubvolume
+```
+
+**Use swapfile:**
+```shell
+touch /swapfile
+chattr +C /swapfile
+fallocate -l 8G /swapfile
+chmod 0600 /swapfile
+mkswap /swapfile
+swapon /swapfile
+```
+
+## Filesystem Usage
+**See Usage**:
+```shell
+btrfs filesystem usage /
+```
+
+**Available Space:**
+```shell
+btrfs filesystem df /
+```
+
+## Scrub
+Btrfs can self heal itself or check for errors with scrubbing.
+**Start:**
+```shell
+btrfs scrub start /
+```
+
+**See Status:**
+```shell
+btrfs scrub status /
+```
+
+## Balance
+Rebalance the filesystem.
+```shell
+btrfs balance start --bg /
+btrfs balance status /
+```
+
+## Snapshots
+Btrfs can use snapshots
+```shell
+btrfs subvolume snapshot source [dest/]name
+````
+
+## Resizing
+Btrfs can be resized.
+
+**To extend the file system size to the maximum available size of the device:**
+```shell
+btrfs filesystem resize max /
+```
+
+**To extend the file system to a specific size:**
+```shell
+btrfs filesystem resize size /
+```
+
+**Add or remove size**
+```shell
+btrfs filesystem resize +size /
+btrfs filesystem resize -size /
+```