First Backup

To create the configuration for a backup, first create a folder on the target that will store the backups. You can save all the backups in a single folder or create a separate directory, including subfolders, for each backup to ensure a better overview. In testing, I created backups on an external drive, on Google Drive, and on a web server via WebDAV.

For example, to store a backup on an external SSD in the Duplicati/ folder you created earlier, click Add Backup and decide in the first step whether you want to create a new configuration or use an existing one. You will typically choose a new configuration here. After clicking Next, you will see five items in a bar at the top that guide you to the finished backup. They are titled General, Destination, Source Data, Schedule, and Options and are largely self-explanatory.

Use General to assign a name and, optionally, a description for the backup. You can then choose a cryptographic method, for which you need to provide a passphrase. The following applies: The stronger the password, the better the encryption. Alternatively, you can disable encryption. In the next step, select the target (Figure 1) and click Test connection. Assuming the software can access the target, you can press Next to continue.

Figure 1: In Duplicati, you first need to specify the target and then the source of the backup. To define the Storage Type you can expand the list of supported protocols and services.

The third step is to select the source data (Figure 2). The data can be filtered by predefined criteria to exclude files from the backup. You then need to define a schedule that determines the backup frequency. If the tool misses a specified backup time, for example, because the computer was not switched on or the target was unreachable, Duplicati automatically catches up at the next opportunity.

Figure 2: Select the source data you want to back up and then decide which filters to set and which data to exclude.

In the final step (Figure 3), you need to determine the size of the chunks that Duplicati uses to store your data and specify how many backups you want to keep and for how long. The Backup retention option takes this decision off your plate and meaningfully reduces the number of backups it keeps as the backups become older.

Figure 3: The last configuration step relates to the general settings. Determine the size of the chunks and the retention time for the backups.

Now save the configuration, which will then appear in Home (Figure 4). You can trigger a backup manually or simply wait for the first scheduled backup to happen. A drop-down box lets you display additional options for each backup. Among other things, you can view a logfile of the various backups in this way (Figure 5).

Figure 4: Once the backup is complete, you will see its details in the Home tab.

Figure 5: In the Home tab, you can open the options for the individual backups by clicking on the drop-down icon to the right of the backup name.

Google Drive

The procedure for backing up to a directory on Google Drive is not that much different from backing up locally. Select Google Drive as the target and specify the path along with the folder you created for the backup earlier on. Then click on AuthID to establish the connection between Duplicati and Google Drive (Figure 6). The rest of the procedure follows the steps for a local backup (Figure 7).

Figure 6: Authenticate to Google Drive from Duplicati by creating an AuthID, which is automatically copied into the field provided. There is nothing standing in the way of creating a backup now.

Figure 7: Transferring to Google Drive was not exactly a fast process in testing, but, at the end of the day, the encrypted data ended up in the right place.

WebDAV

A Nextcloud instance on a remote web server accessible via WebDAV is another potential target. It makes sense to create the duplicati folder up front (Figure 8). For the backup, select WebDAV as the storage type and check the Use SSL box. For the Server and port, enter, for example, nextcloud.example.com followed by a path, such as remote.php/webdav/duplicati. You can usually leave out the port. After entering the username and password for Nextcloud, first check the connection and then start the backup (Figure 9).

Figure 8: Duplicati supports any service that supports a WebDAV connection. I chose a Nextcloud instance, which runs on a web server on the network.

Figure 9: The backup to Nextcloud also worked without any trouble, and Duplicati made full use of the available bandwidth.