Plesk is inaccessible with the following error:
PLESK_INFO: Server Error
DB query failed: SQLSTATE[HY000]: General error: 1 Can’t create/write to file ‘/tmp/#sql_434_0.MYD’ (Errcode: 17), query was: DESCRIBE `sessions`
Temporary file cannot be written to because it was not removed from a past session and it’s unwritable by the current session
Connect to the server via SSH
Restart MySQL server:
# service mariadb restart | service mysqld restart | service mysql restart
Note: In case the issue reoccurs, MySQL server parameters like innodb_ buffer_ pool_size should be optimized in accordance with the server load.