Issue Backup error. Error: Failed to exec mysqldump: Exit code: 3

[zed2007]

Server operating system version

Ubuntu 22.04.2 LTS

Plesk version and microupdate number

Version 18.0.50 Update #2

After migrating the domain to a new server, I had problem with the backup.

Warning: Database "usr_p361672_1"
Unable to make database dump. Error: Failed to exec mysqldump: Exit code: 3: WARNING: Forcing protocol to TCP due to option specification. Please explicitly state intended protocol. mysqldump: Error 2013: Lost connection to server during query when dumping table `magnalister_orders` at row: 520811
Warning: Database "usr_p361672_1"
Unable to back up database usr_p361672_1. Error: DB query failed: SQLSTATE[HY000] [2002] No such file or directory

Which is also interesting, the first 3 backups (1 Full + 2 Incr.) were without errors.
Also, on the previos server was MariaDB 10.2 , and on the new server - 10.6

 

[Peter Debik]

It seems that the database server crashed during the dump. This often happens when a corrupt table or index file is encountered. This symptom does not occur during regular operations, because it needs the access attempt to the corrupt file which may not take place in regular operations. It would be good to look for "mariadb" related entries in /var/log/messages to find out more details on what happened immediately before the crash. Normally you will find entries there describing the issue, e.g. mentioning a file, a database or table.

 

[zed2007]

Yes, indeed, the database sever is behaving strangely. Here are the logs during the start of the backup. And before database crash.

 

[Peter Debik]

That is not the right "look". You'll need to find the location where the restart is logged. Before that you'll find a sequence what happenend that a restart attempt was necessary. Or a shutdown attempt. Try searching for the right timecode with
# grep mariadb /var/log/messages | grep shutdown