manage-replication.md

Manage Replication

HarperDB instance clustering and replication can be configured directly through the HarperDB Studio. It is recommended to read through the clustering documentation first to gain a strong understanding of HarperDB clustering behavior.

All clustering configuration is handled through the replication page of the HarperDB Studio, accessed with the following instructions:

1. Navigate to the HarperDB Studio Organizations page.

2. Click the appropriate organization that the instance belongs to.

3. Select your desired instance.

4. Click replication in the instance control bar.

Note, the replication page will only be available to super users.

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Initial Configuration

HarperDB instances do not have clustering configured by default. The HarperDB Studio will walk you through the initial configuration. Upon entering the replication screen for the first time you will need to complete the following configuration. Configurations are set in the enable clustering panel on the left while actions are described in the middle of the screen. It is worth reviewing the Creating a Cluster User document before proceeding.

1. Enter Cluster User username. (Defaults to cluster_user).
2. Enter Cluster Password.
3. Review and/or Set Cluster Node Name.
4. Click Enable Clustering.

At this point the Studio will restart your HarperDB Instance, required for the configuration changes to take effect.

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Manage Clustering

Once initial clustering configuration is completed you a presented with a clustering management screen with the following properties:

• connected instances

  Displays all instances within the Studio Organization that this instance manages a connection with.

• unconnected instances

  Displays all instances within the Studio Organization that this instance does not manage a connection with.

• unregistered instances

  Displays all instances outside the Studio Organization that this instance manages a connection with.

• manage clustering

  Once instances are connected, this will display clustering management options for all connected instances and all databases and tables.

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Connect an Instance

HarperDB Instances can be clustered together with the following instructions.

1. Ensure clustering has been configured on both instances and a cluster user with identical credentials exists on both.

2. Identify the instance you would like to connect from the unconnected instances panel.

3. Click the plus icon next the appropriate instance.

4. If configurations are correct, all databases will sync across the cluster, then appear in the manage clustering panel. If there is a configuration issue, a red exclamation icon will appear, click it to learn more about what could be causing the issue.

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Disconnect an Instance

HarperDB Instances can be disconnected with the following instructions.

1. Identify the instance you would like to disconnect from the connected instances panel.

2. Click the minus icon next the appropriate instance.

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Manage Replication

Subscriptions must be configured in order to move data between connected instances. Read more about subscriptions here: Creating A Subscription. The manage clustering panel displays a table with each row representing an channel per instance. Cells are bolded to indicate a change in the column. Publish and subscribe replication can be configured per table with the following instructions:

1. Identify the instance, database, and table for replication to be configured.

2. For publish, click the toggle switch in the publish column.

3. For subscribe, click the toggle switch in the subscribe column.