4.3 Setting Up Oracle GoldenGate for Big Data in a High Availability Environment

This topic describes the best practices of achieving high availability of Oracle GoldenGate for Big Data processes.

Topics:

• Running Oracle GoldenGate for Big Data from a Single Instance
  
• Running Oracle GoldenGate for Big Data on a Cluster of Servers
  
• Shared Storage
  Most shared storage solutions, including general purpose cluster file systems, can be used to install Oracle GoldenGate or to store the files that Oracle GoldenGate needs to recover.

4.3.1 Running Oracle GoldenGate for Big Data from a Single Instance

To configure the single server high availability, you need to configure the manager process with AUTOSTART and AUTORESTART parameters. These parameters ensure that the manager process always gets the extract or replicat group to be started back up from an inactive state.

4.3.2 Running Oracle GoldenGate for Big Data on a Cluster of Servers

Depending on which cluster manager software that is being used, you need to configure it to ensure the following:

• There is exactly one active node that is running Oracle GoldenGate for Big Data. It is assumed that the cluster manager can detect that a compute node is down and subsequently spawn another node to be the active.
• Install Oracle GoldenGate for Big Data in shared file system and have that shared file system mounted in the same location for all the nodes participating in the High Availability (HA) configuration. For more information about installing Oracle GoldenGate for Big Data, see Installing Oracle GoldenGate for Big Data in the Installing and Upgrading Oracle GoldenGate for Big Data guide. Most of the state files, including the Input and Output Trail files, Configuration files, and Checkpoint files described in the next point are stored in sub-directories of the Oracle GoldenGate for Big Data install. The Oracle GoldenGate for Big Data installation directory is the same across all managed nodes. This helps the administrator to leverage the exact content of entry point script to bring up Oracle GoldenGate for Big Data as part of its workflow to spawn a new active node. An example of the content of the entry point script is a command to start the Oracle GoldenGate manager process.
• Oracle GoldenGate artifacts are stored in one or more shared file systems or volumes accessible from all nodes. For more information about these files, see Directory Structure in the Installing and Upgrading Oracle GoldenGate for Big Data guide:
  • Input and Output Trail files: Typically these files are located in the gg_install_dir/dirdat directory, where gg_install_dir is the Oracle GoldenGate installation directory, such as C:/ggs on Windows or /home/user/ggs on UNIX. These files are configurable.
  • Configuration files: The configuration files are located in the gg_install_dir/dirprm directory.
  • Checkpoint files: These files are stored in an internal subdirectory, such as the gg_install_dir/dirchk directory.
  • When using File Writer features, for example, File Writer handler, ADW, or Redshift integration, the file writer output files and the state files must be on shared volumes.

For more information about configuring cluster high availability for handlers, see Configuring Cluster High Availability in Using Oracle GoldenGate for Big Data guide.

4.3.3 Shared Storage

Most shared storage solutions, including general purpose cluster file systems, can be used to install Oracle GoldenGate or to store the files that Oracle GoldenGate needs to recover.

The following options are available from Oracle:

• Oracle Cluster File System (OCFS2) –available only on Linux: OCFS2 can also be used for Oracle Database storage, although Oracle recommends the use of Oracle Automatic Storage Management (ASM) starting with Oracle Database 10g. For more information, see http://oss.oracle.com/projects/ocfs2/.
• Oracle Automatic Storage Management (ASM) Cluster File System (ACFS): For more information about the Oracle Database 11g Release 2 ACFS, see Oracle Database Automatic Storage Administrator's Guide as part of the Oracle Database 11g Release 2 documentation set: https://docs.oracle.com/cd/E11882_01/server.112/e18951/asmfs_util001.htm#OSTMG91000.
• Oracle Database File System (DBFS): For more information about DBFS, its restrictions as well as how to configure a DBFS, see Oracle Database Secure File and Large Objects Developer's Guide from the Oracle Database 11g Release 2 documentation set: https://docs.oracle.com/cd/E11882_01/appdev.112/e18294/adlob_fs.htm#BABDHGGJ.
• Oracle ACFS with Oracle Database 11g Release 2