Working with FSx for OpenZFS snapshots

A snapshot is a read-only image of an FSx for OpenZFS volume at a point in time. Snapshots offer protection against accidental deletion or modification of files in your volumes. With snapshots, your users can easily view and restore individual folders and files from an earlier snapshot. Doing this enables users to easily undo changes and compare file versions.

Because snapshots are stored alongside your file system's data, they consume the file system's storage capacity. However, snapshots consume storage capacity only for the changed portions of files since the last snapshot.

Snapshots are stored in the .zfs/snapshot directory at the root of a volume.

Topics

• Using snapshots to create volumes
• Creating a snapshot
• Deleting a snapshot
• Viewing a snapshot
• Restoring a volume from a snapshot
• Restoring individual files and folders
• Setting up a custom snapshot schedule
• On-demand data replication

Using snapshots to create volumes

You can use a snapshot to create a clone volume or a full-copy volume.

A clone volume is a writable copy that is initialized with the same data as the snapshot from which it was created. Clone volumes provide an easy way to support multiple users or applications in parallel from a shared dataset, as well as quickly test new changes to your databases or applications. Clone volumes are created almost instantly and initially consume no additional storage capacity. (They only consume capacity for incremental changes to the source snapshot.) However, each clone volume maintains a dependency on its source snapshot, so you cannot delete this source snapshot while the clone volume is in use. To split a clone from its source snapshot and remove this dependency, you must create a new full-copy volume from that clone.

A full-copy volume is also initialized with the same data as its source snapshot, but is a fully independent writable copy. However, because a full-copy volume requires transferring all of the data from the source snapshot, it can take a significantly longer time to create than a clone volume. Once a full-copy volume is created, it is identical to a standard FSx for OpenZFS volume and does not maintain any relationship to its source snapshot.

For more information on creating clone and full-copy volumes, see Managing FSx for OpenZFS volumes.

Creating a snapshot

You can create an FSx for OpenZFS snapshot using the Amazon FSx console, the AWS CLI, and the Amazon FSx API.

To create a snapshot (console)

1. Open the Amazon FSx console at https://console.aws.amazon.com/fsx/.

2. In the left navigation pane, under OpenZFS, choose Snapshots. Then in the Snapshots pane, choose Create snapshot.

   You can also create a snapshot directly by navigating to the Snapshots tab of an individual volume and choosing Create snapshot.

3. In the File system field of the Create snapshot dialog box, choose the file system to create the snapshot on.

4. In the Volume field, choose an existing volume you want to take a snapshot of.

5. In the Snapshot name field, provide a name for the snapshot. You can use a maximum of 203 alphanumeric characters, and the special characters . - _ :

6. Choose Confirm to create the snapshot.

The snapshot is ready for use when its status is Available.

To create a snapshot (CLI)

• To create an FSx for OpenZFS snapshot, use the create-snapshot CLI command (or the equivalent CreateSnapshot API operation), as shown in the following example.

  aws fsx create-snapshot \
      --volume-id fsvol-123 \
      --name snapshot2

The command example uses the following parameters:

• volume-id - The ID of the volume that you are taking a snapshot of.

• name - The name of the source snapshot.

After successfully creating the snapshot, Amazon FSx returns its description in JSON format.

Deleting a snapshot

You can delete an FSx for OpenZFS snapshot using the Amazon FSx console, the AWS CLI, and the Amazon FSx API. After deletion, the snapshot no longer exists, and its data is gone. Deleting a snapshot doesn't affect snapshots stored in a file system backup.

Note

A snapshot can't be deleted if it was previously cloned and that clone is still available. Before you can delete the snapshot, you must first delete all of the snapshot's clones.

To delete a snapshot (console)

1. Open the Amazon FSx console at https://console.aws.amazon.com/fsx/.

2. In the left navigation pane, under OpenZFS,choose Snapshots.

3. In the Snapshots page, choose the snapshot that you want to delete.

4. In the Summary page for the snapshot, choose Delete.

To delete a snapshot (CLI)

• To delete an FSx for OpenZFS volume, use the delete-volume CLI command (or the equivalent DeleteVolume API operation), as shown in the following example.

  aws fsx delete-snapshot --snapshot-id fsvolsnap-1234

Viewing a snapshot

You can see the FSx for OpenZFS volumes that are currently on your file system using the Amazon FSx console, the AWS CLI, and the Amazon FSx API and SDKs.

To view the snapshots on your file system:

• Using the console – Choose a file system to view the File systems detail page. Choose the Volumes tab to list all the volumes on the file system, and then choose a volume. The volume's Summary page has a Snapshots tab that lists the snapshots for the volume.

• Using the CLI or API – Use the describe-snapshots CLI command or the DescribeSnapshots API operation.

Restoring a volume from a snapshot

You can return a volume to a state saved by a specified snapshot. You use the restore-volume-from-snapshot CLI command (or the equivalent RestoreVolumeFromSnapshot API operation), as shown in the following example.

aws fsx restore-volume-from-snapshot \
    --volume-id fsvol-12345 \
    --snapshot-id fsvolsnap-67890 \
    --options DELETE_INTERMEDIATE_SNAPSHOTS DELETE_CLONED_VOLUMES

The command example uses the following parameters:

• volume-id - The ID of the volume that you are restoring.

• snapshot-id - The ID of the source snapshot. Specifies the snapshot you are restoring from.

• DELETE_INTERMEDIATE_SNAPSHOTS - Deletes snapshots between the current state and the specified snapshot. restore-volume-from-snapshot will fail if there are intermediate snapshots and this option isn't used.

• DELETE_CLONED_VOLUMES - Deletes any volumes cloned from this volume. restore-volume-from-snapshot will fail if there are any cloned volumes and this option isn't used.

Restoring individual files and folders

Using the snapshots on your Amazon FSx file system, your users can quickly restore previous versions of individual files or folders. Doing this enables them to recover deleted or changed files stored on the shared file system. They do this in a self-service manner directly on their desktop without administrator assistance. This self-service approach increases productivity and reduces administrative workload.

Linux, macOS, and Windows clients can view snapshots in the .zfs/snapshot directory hidden at the root of a volume. The .zfs directory is hidden, so it will not appear in any ls or dir results. You must also specify the crossmnt option in the NFS exports configuration of your FSx for OpenZFS volume to enable your clients to navigate to this directory.

To restore a file from a snapshot (Linux, macOS, and Windows clients)

1. If the original file still exists and you do not want it overwritten by the file in a snapshot, then use your Linux, macOS, or Windows client to rename the original file or move it to a different directory.

2. In the .zfs/snapshot directory, locate the snapshot that contains the version of the file that you want to restore.

3. Copy the file from the .zfs/snapshot directory to the directory in which the file originally existed.

Data in snapshots is read only. If you want to make modifications to files and folders in a snapshot, you must save a copy of the files and folders to a writable location and make modifications to these copies.