Dump Mode

Interaction between Backup and Binary Logs

During a database’s life, MySQL generates logs that can be used to replicate and/or protect your database using P.I.T.R (Point In Time Recovery).

By default, the MySQL Plugin will dump each database one at a time. This means that if you restore the entire server, the databases will be consistent separately, because they were not backed up at exactly the same time, the databases will not be globally consistent. To address this issue, the Bacula Enterprise MySQL Plugin will also save log files generated during the backup. These log files may later be played back to ensure that the databases are consistent at a particular point in time.

In the example presented in the figure above, during the backup of the databases “DB1”, “DB2” and “DB3” (that can take several hours), 3 log files (logs 2, 3, and 4) were generated, and will be included in the Full backup.

The next Incremental or Differential backup will save only new binary logs generated after the Full. To ensure that only one copy of each log file is included in your backup, you should activate the Accurate option for your Job.

In the example shown above, the first Incremental job after the Full backup will include logs 5 and 6, and the second Incremental job will include logs 7 and 8. A Differential backup would include log files 5, 6, 7 and 8.

When you use the all_databases option on the Plugin command line, all databases will be dumped at the same time, and the log files will not be flushed at the end of the Full backup, but logs generated before the end of the job are included in the backup. In the example shown in the figure below, the Full backup will generate a single dump all-databases.sql and will include log files 2 and 3, but not log file 4. The first subsequent Incremental backup will include log files 4, 5 and 6.