Replication Tasks
6 minute read.
TrueNAS replication allows users to create one-time or regularly scheduled snapshots of data stored in pools, datasets or zvols on their TrueNAS system as a way to back up stored data. When properly configured and scheduled, replication takes regular snapshots of storage pools or datasets and saves them in the destination location either on the same system or a different system.
Replication from one pool or dataset to another pool or dataset on the TrueNAS system is called local replication. Replication from the TrueNAS system to another TrueNAS or other backup server is called remote replication. Both local and remote replication can involve encrypted pools or datasets.
The sections below provide overviews on what to do before you begin configuring a replication task.
Local replication does not require the admin user to have SSH access, a home directory, or sudo command permissions. Setting options change based on the source and destination selections. Replicating to or from a local source does not require an SSH connection.
Set up the data storage for replicated snapshots. Go to Datasets to add a dataset to store the replicated data (snapshots). TrueNAS does not allow you to create a new dataset using the Source file browser in the replication wizard or the Add Replication Task configuration screen. Use the file browser to select the existing dataset on the system where you want to store replicated data.
The Destination file browser allows you to specify (create) a directory in an existing dataset on a local or remote system, but you cannot create a directory for a dataset selected in the Source file browser.
Create a periodic snapshot task of the storage locations to back up. TrueNAS typically creates a periodic snapshot task right before it performs the replication task if one is not already created for the task. You might need to refresh the screen cache to see the task listed in the Periodic Snapshot Task widget.
Go to Data Protection > Replication Tasks and click Add to open the Replication Task Wizard.
If you want to configure a replication task using advanced setting options on the Add Replication Task screen, click Advanced Replication Creation before entering settings in the replication wizard. Settings do not carry over from the wizard to the advanced task creation screen, and TrueNAS shows the dialog where you must confirm you want to leave the wizard screen before it opens. Immediately switching to the advanced screen does not show the confirmation dialog, and you do not have to enter your settings again.
Remote replication requires that the admin user on the remote system has SSH access, the SSH connection public key added, a home directory, and sudo command permission. The SSH service must be on when running the periodic snapshot and replication tasks. Setting options change based on the source and destination selections.
When setting up remote replication:
Set up the data storage for replicated snapshots. On the remote system, go to Datasets to add a dataset for the replicated data (snapshots).
TrueNAS does not allow you to create a new dataset using the Source or Destination file browsers in the replication wizard or the Add Replication Task configuration screen. After selecting the existing dataset where you want to store replicated data, the Destination file browser allows you to specify (create) a directory in an existing dataset on a local or remote system. You cannot create a directory for a dataset selected in the Source file browser.
Add a home directory for the admin user on the local and the remote systems. The Home Directory path on the Add User or Edit User screen must be set to something other than /var/empty.
Click on the Home Directory setting to show the options.
Select Create Home Directory, then use the file browser to select an existing dataset or use Create Dataset after selecting the parent dataset to create a new dataset for home directories.
See Managing Users for more information on home directories, SSH access, and sudo commands.
Set up an SSH connection in TrueNAS before creating a remote replication task.
You can go to Credentials > Backup Credentials > SSH Connection and click Add to create an SSH connection, or select Generate New on the SSH Connection dropdown in the Replication Task Wizard to create an SSH connection to the remote system.
To configure an SSH connection, you need the IP address or host name for the remote system, and the administrator username and credentials. The administrator user on the remote system must have SSH access and the SSH service enabled so the local TrueNAS system can authenticate and communicate with the remote system.
You can configure the SSH connection while configuring the replication task, but using the Credentials > Backup Credentials > SSH Connection option to add a new connection between the local and remote system allows you to properly configure the administration user associated with the task before you add the replication task. If not properly configured, TrueNAS shows error messages stating the issue preventing you from continuing.
Using the Add SSH Connection screen creates the connection and keypair. You can obtain the public key from the keypair screen to copy/paste into the admin user on both the local and remote systems before you open the replication wizard.
Update the admin user settings to to allow SSH access, add the public key for the SSH credential for the remote system, and allow sudo commands.
Go to Credentials > Backup Credentials > SSH Credential. Add a new credential to the remote system if one does not exist, and then edit it to see the public key. Copy the public key to add to the admin user on the remote system. You can add the credential on the local or remote system.
On the remote system, go to Credentials > Users, select the admin user, and click Edit. Verify the account configuration has SSH Access selected. If not, select it, and then paste the public key for the SSH connection in the Public SSH Key field.
Click on Sudo Commands and select Allow all sudo commands with no password to enable it.
Save changes.
Check the SSH Service settings. Go to System > Services > SSH and click the edit icon. Select Allow Password Authentication to enable this function. Save the change.
Incorrect SSH service settings can impact the ability of the admin user to establish an SSH session during replication and require you to obtain and paste a public SSH key into the admin user settings.
Enable Start Automatically if you want the SSH service to start after a system restart, and then start or restart the service.
