F.1.1. Backup Behavior

When a backup is requested, the Tungsten Replicator performs a number of separate, discrete, operations designed to perform the backup operation.

The backup operation performs the following steps:

  1. Tungsten Replicator identifies the filename where properties about the backup will be stored. The file is used as the primary interface between the underlying backup script and Tungsten Replicator.

  2. Tungsten Replicator executes the configured backup/restore script, supplying any configured arguments, and the location of a properties file, which the script updates with the location of the backup file created during the process.

  3. If the backup completes successfully, the file generated by the backup process is copied into the configured Tungsten Cluster directory (for example /opt/continuent/backups.

  4. Tungsten Replicator updates the property information with a CRC value for the backup file and the standard metadata for backups, including the tool used to create the backup.

A log is created of the backup process into a file according to the configured backup configuration. For example, when backing up using mysqldump the log is written to the log directory as mysqldump.log. When using a custom script, the log is written to script.log.

As standard, Tungsten Replicator supports two primary backup types, mysqldump and xtrabackup. A third option is based on the incremental version of the xtrabackup tool. The use of external backup script enables additional backup tools and methods to be supported.

To create a custom backup script, see Section F.1.3, “Writing a Custom Backup/Restore Script” for a list of requirements and samples.