How to use the command 'btrfs subvolume' (with examples)
The command ‘btrfs subvolume’ is used to manage btrfs subvolumes and snapshots. It allows users to create, list, delete, and snapshot subvolumes within a btrfs filesystem. Users can also obtain detailed information about a specific subvolume using this command.
Use case 1: Create a new empty subvolume
Code:
sudo btrfs subvolume create path/to/new_subvolume
Motivation: Creating a new empty subvolume can be useful when you want to isolate specific data or applications within your btrfs filesystem. It allows you to organize your data effectively.
Explanation: This command creates a new empty subvolume at the specified path. The ‘sudo’ keyword is used to run the command with administrative privileges. ‘btrfs subvolume create’ is the command to create a subvolume, and ‘path/to/new_subvolume’ is the path where the new subvolume will be created.
Example output:
Create subvolume '%deFgH' at 'path/to/new_subvolume'
Use case 2: List all subvolumes and snapshots in the specified filesystem
Code:
sudo btrfs subvolume list path/to/btrfs_filesystem
Motivation: Listing all subvolumes and snapshots can provide an overview of the existing subvolumes within a btrfs filesystem. This can be helpful for management and organization purposes.
Explanation: This command lists all the subvolumes and snapshots within the specified btrfs filesystem. The ‘sudo’ keyword is used to run the command with administrative privileges. ‘btrfs subvolume list’ is the command to obtain the list, and ‘path/to/btrfs_filesystem’ is the path to the btrfs filesystem.
Example output:
ID 257 gen 99672 top level 5 path subvolume-1
ID 258 gen 99672 top level 5 path subvolume-2
Use case 3: Delete a subvolume
Code:
sudo btrfs subvolume delete path/to/subvolume
Motivation: Deleting a subvolume can be necessary when you no longer need a specific subvolume and want to free up space. It helps in managing storage resources efficiently.
Explanation: This command deletes the specified subvolume from the btrfs filesystem. The ‘sudo’ keyword is used to run the command with administrative privileges. ‘btrfs subvolume delete’ is the command to delete a subvolume, and ‘path/to/subvolume’ is the path to the subvolume you want to delete.
Example output:
Delete subvolume (no-commit): path/to/subvolume
Use case 4: Create a read-only snapshot of an existing subvolume
Code:
sudo btrfs subvolume snapshot -r path/to/source_subvolume path/to/target
Motivation: Creating a read-only snapshot of an existing subvolume can be beneficial when you want to preserve a specific state of the subvolume for future reference. It prevents accidental modifications and acts as a backup.
Explanation: This command creates a read-only snapshot of the specified source subvolume and saves it as a new subvolume at the target location. The ‘-r’ flag specifies that the snapshot should be read-only. ‘sudo’ is used to run the command with administrative privileges. ‘btrfs subvolume snapshot’ is the command to create a snapshot, ‘path/to/source_subvolume’ is the path to the source subvolume, and ‘path/to/target’ is the path where the snapshot will be created.
Example output:
Create snapshot '%deFgH' at 'path/to/target'
Use case 5: Create a read-write snapshot of an existing subvolume
Code:
sudo btrfs subvolume snapshot path/to/source_subvolume path/to/target
Motivation: Creating a read-write snapshot of an existing subvolume can be useful when you want to experiment with changes without modifying the original data. It allows you to make changes and revert them if necessary.
Explanation: This command creates a read-write snapshot of the specified source subvolume and saves it as a new subvolume at the target location. ‘sudo’ is used to run the command with administrative privileges. ‘btrfs subvolume snapshot’ is the command to create a snapshot, ‘path/to/source_subvolume’ is the path to the source subvolume, and ‘path/to/target’ is the path where the snapshot will be created.
Example output:
Create snapshot '%deFgH' at 'path/to/target'
Use case 6: Show detailed information about a subvolume
Code:
sudo btrfs subvolume show path/to/subvolume
Motivation: Showing detailed information about a subvolume can provide insights into its properties, such as the ID, generation, and top-level, helping you understand its characteristics better.
Explanation: This command displays detailed information about the specified subvolume. The ‘sudo’ keyword is used to run the command with administrative privileges. ‘btrfs subvolume show’ is the command to show subvolume information, and ‘path/to/subvolume’ is the path to the subvolume you want to obtain information about.
Example output:
Subvolume ID 257 gen 99672 top level 5 path subvolume-1
Conclusion:
The ‘btrfs subvolume’ command is a powerful tool for managing subvolumes and snapshots within a btrfs filesystem. It provides various capabilities such as creating, listing, deleting, and obtaining detailed information about subvolumes. By learning how to use these use cases effectively, users can organize their data, make backups, and experiment with changes in a controlled manner.
