Setting Up a Local Replication Task

Storage space you allocate to a zvol is only used by that volume, it does not get reallocated back to the total storage capacity of the pool or dataset where you create the zvol if it goes unused. Plan your anticipated storage need before you create the zvol to avoid creating a zvol that exceeds your storage needs for this volume. Do not assign capacity that exceeds what is required for SCALE to operate properly. For more information, see SCALE Hardware Guide for CPU, memory and storage capacity information.

The first snapshot taken for a task creates a full file system snapshot, and all subsequent snapshots taken for that task are incremental to capture differences occurring between the full and subsequent incremental snapshots.

Scheduling options allow users to run replication tasks daily, weekly, monthly, or on a custom schedule. Users also have the option to run a scheduled job on demand.

Replication tasks require a periodic snapshot task. The earlier releases of SCALE required creating a periodic snapshot task before the replication task, but SCALE 22.12 and newer automatically creates the snapshot task when a scheduled replication task starts. To start a replication task using the Run Now option on the Replication Task widget or by selecting Run Once in the Replication Task Wizard, create a periodic snapshot task first.

Before you begin configuring the replication task, first verify the destination dataset you want to use to store the replication snapshots is free of existing snapshots, or that snapshots with critical data are backed up before you create the task.

To create a replication task:

1. Create the destination dataset or storage location you want to use to store the replication snapshots. If using another TrueNAS SCALE system, create a dataset in one of your pools.

2. Verify the admin user home directory, auxiliary groups, and sudo setting on both the local and remote destination systems. Local replication does not require an SSH connection so this only applies to replication to another system.

   If using a TrueNAS CORE system as the remote server, the remote user is always root.

   If using a TrueNAS SCALE system on an earlier release like Angelfish, the remote user is always root.

   If using an earlier TrueNAS SCALE Bluefin system (22.12.1) or you installed SCALE as the root user, then created the admin user after initial installation, you must verify the admin user is correctly configured.

   Verify Admin User Settings expand

   a. Go to Credentials > Local User, click anywhere on the admin user row to expand it. Scroll down to the Home Directory setting. If set to /home/admin, select Create Home Directory, then Click Save.

   

   If set to /nonexistent, first create a dataset to use for home directories, like /tank/homedirs. Enter this in the Home Directory field, make sure this is not read only.

   b. Select the sudo permission level you want the admin user to have. If you select Allow all sudo commands with no password you do not need to make changes. If you select Allowed sudo commands with no password enter /var/sbin/zfs in the Allowed sudo commands field.

   c. Click Save.

4. Click Next to display the scheduling options.

5. Select the schedule and snapshot retention life time.

   a. Select the Replication Schedule radio button you want to use. Select Run Once to set up a replication task you run one time. Select Run On a Schedule then select when from the Schedule dropdown list.

   

   b. Select the Destination Snapshot Lifetime radio button option you want to use. This specifies how long SCALE should store copied snapshots in the destination dataset before SCALE deletes it. Same as Source is selected by default. Select Never Delete to keep all snapshots until you delete them manually. Select Custom to show two additional settings, then enter the number of the duration you select from the dropdown list. For example, 2 Weeks.

6. Click START REPLICATION. A dialog displays if this is the first snapshot taken using the destination dataset. If SCALE does not find a replicated snapshot in the destination dataset to use to create an incremental snapshot, it deletes any existing snapshots found and creates a full copy of the day snapshot to use as a basis for the future scheduled incremental snapshots for this schedule task. This operation can delete important data, so ensure you can delete any existing snapshots or back them up in another location.

   

   Click Confirm, then Continue to add the task to the Replication Task widget. The newly added task shows the status as PENDING until it runs on the schedule you set.

   

   Select Run Now if you want to run the task immediately.

To see a log for a task, click the task State to open a dialog with the log for that replication task.

To see the replication snapshots, go to Datasets, select the destination dataset on the tree table, then select Manage Snapshots on the Data Protection widget to see the list of snapshots in that dataset. Click Show extra columns to add more information columns to the table such as the date created which can help you locate a specific snapshot or enter part of or the full the name in the search field to narrow the list of snapshots.