Problem
A database backup fails or is marked partially complete with the following error: Error 2013: Lost connection to MySQL server during query.
The failure consistently occurs on the same table, yet running mysqldump/mariadb-dump manually from the command line for the same database succeeds.
Cause
This issue is caused by the max_allowed_packet setting being too low. When the backup process encounters a row with a very large amount of data, the data packet exceeds the configured limit, and the database server terminates the connection.
Solution
The fix is to increase the packet size limit directly within the JetBackup 5 settings.
- Navigate to Settings and click the Performance tab.
- Locate the setting Dump max allowed packet under MySQL/MariaDB settings.
- Increase the value to 1 GB.
- Click Save Settings.
After saving, re-run the failed/partially completed backup job to verify that it now completes successfully.
