I used this guide
in step three, after the command:
mysql -u root -p <mysql.dump
I got an error:
ERROR 1036 (HY000) at line 89: Table ‘entries’ is read only
(maybe someone can explain its cause, for future generations =)
further actions probably led to the complete collapse of the database.
My solution of the problem was a complete rollback of the virtual machine.
ps
error 503 may cause a problem with the tc.log file
In the logs, it looks like:
[Note] InnoDB: Dumping buffer pool (s) not yet started
[Note] Recovering after a crash using tc.log
[ERROR] Can’t init tc log
[ERROR] Aborting
The solution is simple:
delete the file /var/lib/mysql/tc.log
and run command
systemctl restart mariadb