TrueNAS SCALE Nightly Development Documentation
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Snapshots

5 minute read.

Last Modified 2024-04-09 12:55 EDT

The Snapshots screen lists dataset snapshots on the system. It allows you to add new or manage existing snapshots.

Access to the Snapshots screen is available using the Manage Snapshots link on the Data Protection widget on the Datasets screen and by clicking Snapshots on the Periodic Snapshot Tasks widget on the Data Protection screen.

If the selected dataset does not have snapshots, the screen displays No Snapshots are Available.

Enter a dataset path in the search field at the top of the screen to check for snapshots for other datasets.

My Snapshot screen is blank

If the Snapshots screen does not display a list of snapshots and you know you added snapshots, clear the dataset path in the search field to show all dataset and zvol snapshots on the system.

Add opens the Add Snapshot screen.

Select the checkbox to the left of each snapshot to select multiple snapshots and display the Batch Operations option to Delete the selected snapshots.

Show Extra Snapshot List Columns

Click the Show Extra Columns toggle to add extra information columns to the list of snapshots to open the Show Extra Columns dialog.

Show adds the extra columns to the list of snapshots. These columns add the space used (Used), the snapshot creation date, and the amount of data the dataset can access (Referenced).

Click the toggle again to open the Hide Extra Columns dialog. Hide to return to the default view with only the Dataset and Snapshot columns.

Snapshot Details Screen

Click anywhere on a snapshot to expand it and view more information about the snapshot and the options for that snapshot.

Select the checkbox to the left of each snapshot to select multiple snapshots and display the Batch Operations option to Delete the selected snapshots.

Option	Description
Delete	Opens a Delete confirmation dialog for the selected snapshot(s). Select Confirm to activate the Delete button.
Clone to New Dataset	Opens the Clone to New Dataset) window where you enter a new name or clone with the default value in the Dataset Name field.
Rollback	Opens the Dataset Rollback From Snapshot window with three radio button options. Confirm activates the Rollback button.
Hold	Select to prevent the snapshot from being deleted. If selected and you batch-operation delete datasets, this opens an error display with the name of the dataset and prevents the delete operation from continuing.

Rollback from Snapshot Window

The snapshot Rollback option replaces the data in the selected dataset with the information saved in the snapshot.

WARNING: Rolling the dataset back destroys data on the dataset and can destroy additional snapshots that are related to the dataset. This can result in permanent data loss! Do not roll back until all desired data and snapshots are backed up.

There are three Stop Rollback if Snapshot Exists radio button options that impose safety levels on the rollback operation. When the safety check finds additional snapshots directly related to the dataset you are rolling back it cancels the rollback.

Rollback Options

Setting	Description
Newer Intermediate, Child, and Clone	Select to stop rollback when the safety check finds any related intermediate, child dataset, or clone snapshots that are newer than the rollback snapshots.
Newer Clone	Select to stop rollback when the safety check finds any related clone snapshots newer than the rollback snapshot.
No Safety Check (CAUTION)	Select to stop rollback if snapshot exists. The rollback destroys any related intermediate, child dataset, and cloned snapshots newer than the rollback snapshot.
Confirm	Select to confirm the selection and activate the Rollback button.

Clone Snapshot and Promote Dataset

Cloning to New Dataset

Use the Clone to New Dataset button to create a clone of the snapshot. The clone appears directly beneath the parent dataset in the dataset tree table on the Datasets screen. Click Clone to New Dataset to open a clone confirmation dialog.

Click Clone to confirm.

The Go to Datasets button opens the Datasets screen.

Promoting a Dataset

Click on the clone name in the dataset listing to populate the Dataset Details widget and display the Promote button.

After clicking the Promote button, the dataset clone is promoted and this button no longer appears.

Promote now displays on the Dataset Details widget when you select the demoted parent dataset.

Figure 12: Demoted Dataset with Promote Button

See zfs-promote.8 for more information.

Delete Snapshot

The snapshot Delete option opens a window that lists the snapshot(s) you select.

Confirm activates the Delete button.

Batch Operations - Delete

To delete more than one snapshot in one operation, select the checkbox beside the datasets you want to delete to display the Batch Operations Delete option.

Batch Operations Delete opens a window listing all selected snapshots.

Confirm activates the Delete button. If a snapshot has the Hold option selected, an error displays to prevent you from deleting that snapshot.

Add Snapshot Screen

The Add Snapshots screen allows you to create a snapshot while on the Snapshots screen. It also opens when you click Create Snapshot on the Dataset Protection widget on the Datasets screen.

Save retains the settings and returns to the Snapshots screen.

Add Snapshot Settings

Setting	Description
Dataset	Select the dataset or zvol from the dropdown list. The snapshot created is from this dataset or zvol.
Name	TrueNAS populates this with a name but you can override the name with any string of your choice. You cannot use Name and Naming Schema for the same snapshot.
Naming Schema	Select an option from the dropdown list or leave this blank to use the system-populated name in the Name field. This generates a name for the snapshot using the naming schema from a previously-entered periodic snapshot. This allows replication of the snapshot. You cannot use Naming Schema with Name. Selecting a schema option overwrites the value in Name.
Recursive	Select to include child datasets or zvols in the snapshot.