Replicate HDFS Data to Multiple Databases

Always-on applications rely on automatic failover capabilities and real-time access to data. CData Sync integrates live HDFS data into your mirrored databases, always-on cloud databases, and other databases such as your reporting server: Automatically synchronize with remote HDFS data from Windows.

Configure Replication Destinations

Using CData Sync, you can replicate HDFS data to any number of databases, both cloud-based and on-premises. To add a replication destination, navigate to the Connections tab.

For each destination database:

1. Click Add Connection.
2. Select a destination. In this article, we use SQLite.
3. Enter the necessary connection properties. To replicate HDFS to a SQLite database, enter a file path in the Data Source box.
4. Click Test Connection to ensure that the connection is configured properly.
5. Click Save Changes.

Configure the HDFS Connection

You can configure a connection to HDFS from the Connections tab. To add a connection to your HDFS account, navigate to the Connections tab.

1. Click Add Connection.
2. Select a source (HDFS).
3. Configure the connection properties.
   
   

   In order to authenticate, set the following connection properties:

   • Host: Set this value to the host of your HDFS installation.
   • Port: Set this value to the port of your HDFS installation. Default port: 50070
4. Click Connect to ensure that the connection is configured properly.
5. Click Save Changes.

Configure Replication Queries

CData Sync enables you to control replication with a point-and-click interface and with SQL queries. For each replication you wish to configure, navigate to the Jobs tab and click Add Job. Select the Source and Destination for your replication.

Replicate Entire Tables

To replicate an entire table, click Add Tables in the Tables section, choose the table(s) you wish to replicate, and click Add Selected Tables.

Customize Your Replication

You can use a SQL query to customize your replication. The REPLICATE statement is a high-level command that caches and maintains a table in your database. You can define any SELECT query supported by the HDFS API. To customize your replication, click Add Custom Query in the Tables section and define the Query Statement.

The statement below caches and incrementally updates a table of HDFS data:

REPLICATE Files;

You can specify a file containing the replication queries you want to use to update a particular database. Separate replication statements with semicolons. The following options are useful if you are replicating multiple HDFS accounts into the same database:

• Use a different table prefix in the REPLICATE SELECT statement:

  REPLICATE PROD_Files SELECT * FROM Files;

• Alternatively, use a different schema:

  REPLICATE PROD.Files SELECT * FROM Files;

Schedule Your Replication

In the Schedule section, you can schedule a job to run automatically, configuring the job to run after specified intervals ranging from once every 10 minutes to once every month.

Once you have configured the replication job, click Save Changes. You can configure any number of jobs to manage the replication of your HDFS data to disparate on-premises, cloud-based, and other databases.