Valid values are 'ON' and 'OFF' select @@global.innodb_read_only; @@global.innodb_read_only 0 select @@session.innodb_read_only; ERROR HY000: Variable 'innodb_read_only' is a GLOBAL variable show global variables like 'innodb_read_only'; Variable_name Value innodb_read_only OFF show session variables like 'innodb_read_only'; Variable_name Value innodb_read_only OFF select * from information_schema.global_variables where variable_name='innodb_read_only'; VARIABLE_NAME VARIABLE_VALUE INNODB_READ_ONLY OFF select * from information_schema.session_variables where variable_name='innodb_read_only'; VARIABLE_NAME VARIABLE_VALUE INNODB_READ_ONLY OFF set global innodb_read_only=1; ERROR HY000: Variable 'innodb_read_only' is a read only variable set session innodb_read_only=1; ERROR HY000: Variable 'innodb_read_only' is a read only variable