How to use the command 'btrfs property' (with examples)

The btrfs property command is a versatile tool for managing properties on BTRFS filesystem objects, including files, directories, subvolumes, filesystems, and devices. This command allows for listing available properties, retrieving current property values, and setting specific properties on BTRFS objects. These capabilities are crucial for administrators who want to fine-tune filesystem performance or behavior through property adjustments.

Use case 1: List available properties (and descriptions) for the given BTRFS object

Code:

sudo btrfs property list path/to/btrfs_object

Motivation: When managing a BTRFS filesystem, it is often necessary to know what properties can be manipulated or monitored. Listing available properties provides valuable insight into what configurations and optimizations you can apply to your filesystem resources, aiding both in performance tuning and system analysis.

Explanation:

• sudo: This is required to execute the command with root privileges, which is necessary for accessing filesystem properties.
• btrfs property list: Instructs the command to list properties that can be managed on BTRFS objects.
• path/to/btrfs_object: Specifies the path to the BTRFS object (file, directory, subvolume, etc.) whose properties you want to list, giving you a broad overview of all modifiable settings.

Example Output:

ro            (read-only, bool, default:false)
compression   (compression algorithm, 'zstd'| ‘zlib’|‘lzo’|none, default:none)
label         (filesystem label, string, default:"")

Use case 2: Get all properties for the given BTRFS object

Code:

sudo btrfs property get path/to/btrfs_object

Motivation: Understanding the current state of your BTRFS object properties is crucial for maintenance and troubleshooting. Retrieving all properties with their current values allows administrators to gain visibility into filesystem configurations and perform audits or comparisons effectively.

Explanation:

• sudo: Executes the command with administrative permissions to access and modify filesystem settings.
• btrfs property get: Command to fetch current property settings on the specified object.
• path/to/btrfs_object: Defines the path to the BTRFS object you wish to query, ensuring you receive accurate and relevant information for that specific resource.

Example Output:

label: my-filesystem
ro: false
compression: zstd

Use case 3: Get the label property for the given BTRFS filesystem or device

Code:

sudo btrfs property get path/to/btrfs_filesystem label

Motivation: Filesystem labels are helpful identifiers that assist in distinguishing between various filesystems, especially when managing multiple BTRFS volumes. By retrieving the label property, administrators can verify or document the label associated with the filesystem, aiding in organization and operational clarity.

Explanation:

• sudo: Needed to perform the operation with adequate permissions.
• btrfs property get: Command used to query property values.
• path/to/btrfs_filesystem: Indicates the specific filesystem or device to query.
• label: Specifies that only the ’label’ property should be retrieved, focusing the query and reducing unnecessary data retrieval.

Example Output:

label: my-data-vol

Use case 4: Get all object type-specific properties for the given BTRFS filesystem or device

Code:

sudo btrfs property get -t subvol|filesystem|inode|device path/to/btrfs_filesystem

Motivation: Different object types within BTRFS may support different sets of properties. By specifying the object type, administrators can retrieve a concise list of properties unique to that object type, ensuring the information is pertinent and actionable for targeted management tasks.

Explanation:

• sudo: Runs the command with root access.
• btrfs property get: Fetches property information.
• -t subvol|filesystem|inode|device: Filters properties based on the type of BTRFS object (subvolume, filesystem, inode, or device), honing the command output to relevant properties.
• path/to/btrfs_filesystem: Indicates which BTRFS object to target for property inquiries.

Example Output:

compression: zstd
ro: false

Use case 5: Set the compression property for a given BTRFS inode (either a file or directory)

Code:

sudo btrfs property set path/to/btrfs_inode compression zstd|zlib|lzo|none

Motivation: Adjusting the compression property of a BTRFS inode can optimize data storage by reducing file size without compromising data integrity. By setting the compression method (or opting for none), administrators fine-tune disk usage according to operational needs or performance requirements.

Explanation:

• sudo: Employs administrative privileges to alter property settings.
• btrfs property set: Command for changing property values.
• path/to/btrfs_inode: Targets the specific file or directory whose compression property will be altered.
• compression zstd|zlib|lzo|none: Specifies the desired compression method, allowing the user to choose between various algorithms or disable compression altogether.

Example Output:

Setting property succeeded

Conclusion:

The btrfs property command provides comprehensive options for managing and viewing properties across various BTRFS filesystem objects. Through practical examples, this article outlined how to harness this command to list, get, and set properties, thereby enhancing both the understanding and capabilities of BTRFS filesystem administration. Whether optimizing compression or simply auditing the filesystem state, these use cases underscore the command’s value in maintaining robust data management environments.