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Chapter 30. Using snapshots on Stratis file systems
You can use snapshots on Stratis file systems to capture file system state at arbitrary times and restore it in the future.
30.1. Characteristics of Stratis snapshots Copier lienLien copié sur presse-papiers!
Stratis snapshots are regular file systems created as point-in-time copies of other Stratis file systems. They operate independently of their source file system and can be used for backup, testing, or data recovery purposes.
The current snapshot implementation in Stratis is characterized by the following:
- A snapshot of a file system is another file system.
- A snapshot and its origin are not linked in lifetime. A snapshotted file system can live longer than the file system it was created from.
- A file system does not have to be mounted to create a snapshot from it.
- Each snapshot uses around half a gigabyte of actual backing storage, which is needed for the XFS log.
30.2. Creating a Stratis snapshot Copier lienLien copié sur presse-papiers!
You can create a Stratis file system as a snapshot of an existing Stratis file system.
Prerequisites
-
Stratis is installed and the
stratisdservice is running. For more information, see Installing Stratis. - You have created a Stratis file system. For more information, see Creating a Stratis file system.
Procedure
Create a Stratis snapshot:
# stratis fs snapshot my-pool my-fs my-fs-snapshotA snapshot is a first class Stratis file system. You can create multiple Stratis snapshots. These include snapshots of a single origin file system or another snapshot file system. If a file system is a snapshot, then its origin field will display the UUID of its origin file system in the detailed file system listing.
30.3. Accessing the content of a Stratis snapshot Copier lienLien copié sur presse-papiers!
You can mount a snapshot of a Stratis file system to make it accessible for read and write operations.
Prerequisites
-
Stratis is installed and the
stratisdservice is running. For more information, see Installing Stratis. - You have created a Stratis snapshot. For more information, see Creating a Stratis snapshot.
Procedure
To access the snapshot, mount it as a regular file system from the
/dev/stratis/my-pool/directory:# mount /dev/stratis/my-pool/my-fs-snapshot mount-point
30.4. Reverting a Stratis file system to a previous snapshot Copier lienLien copié sur presse-papiers!
You can revert the content of a Stratis file system to the state captured in a Stratis snapshot.
Prerequisites
-
Stratis is installed and the
stratisdservice is running. For more information, see Installing Stratis. - You have created a Stratis snapshot. For more information, see Creating a Stratis snapshot.
Procedure
Optional: Back up the current state of the file system to be able to access it later:
# stratis filesystem snapshot my-pool my-fs my-fs-backupSchedule a revert of your file system to the previously taken snapshot:
# stratis filesystem schedule-revert my-pool my-fs-snapshotOptional: Run the following to check if the revert is scheduled successfully:
# stratis filesystem list my-pool --name my-fs-snapshotUUID: b14987eb-b735-4c68-8962-f53f6b644cbc Name: my-fs-snapshot Pool: my-pool Device: /dev/stratis/p1/my-fs-snapshot Created: Mar 18 2025 12:29 Snapshot origin: f5a881b1-299d-4147-8ead-b4a56c623692 Revert scheduled: Yes Sizes: Logical size of thin device: 1 TiB Total used (including XFS metadata): 5.42 GiB Free: 1018.58 GiBNoteIt is not possible to schedule more than one revert operation into the same origin filesystem. Also, if you try to destroy either the origin file system, or the snapshot to which the revert is scheduled, the destroy operation fails.
You can also cancel the revert operation any time before you restart the pool:
# stratis filesystem cancel-revert my-pool my-fs-snapshotYou can run the following to check if the cancellation is scheduled successfully:
# stratis filesystem list my-pool --name my-fs-snapshotUUID: b14987eb-b735-4c68-8962-f53f6b644cbc Name: my-fs-snapshot Pool: my-pool Device: /dev/stratis/p1/my-fs-snapshot Created: Mar 18 2025 12:29 Snapshot origin: f5a881b1-299d-4147-8ead-b4a56c623692 Revert scheduled: No Sizes: Logical size of thin device: 1 TiB Total used (including XFS metadata): 5.42 GiB Free: 1018.58 GiB Size Limit: NoneIf not cancelled, the scheduled revert will proceed when you restart the pool:
# stratis pool stop --name my-pool# stratis pool start --name my-pool
Verification
List the file system belonging to the pool:
# stratis filesystem list my-pool
The my-fs-snapshot now does not appear in the list of file systems in the pool as it is reverted to the previously copied my-fs-snapshot state. The content of the file system named my-fs is now identical to the snapshot my-fs-snapshot.
30.5. Removing a Stratis snapshot Copier lienLien copié sur presse-papiers!
You can remove a Stratis snapshot from a pool. Data on the snapshot are lost.
Prerequisites
-
Stratis is installed and the
stratisdservice is running. For more information,see Installing Stratis. - You have created a Stratis snapshot. For more information, see Creating a Stratis snapshot.
Procedure
Unmount the snapshot:
# umount /dev/stratis/my-pool/my-fs-snapshotDestroy the snapshot:
# stratis filesystem destroy my-pool my-fs-snapshot