MySQL my.cnf: innodb_log_file_size is missing How to set innodb_log_file_size to MySQL database if there is no innodb_log_file_size in my.cnf configuration file? I'd like to backup via Percona Xtrabackup and the backup crashes at this point telling me that my innodb_log_file_size is different than it expects.
Login to mysql and run this

SHOW GLOBAL VARIABLES LIKE 'innodb_log_file_size';


or this

SELECT variable_value FROM information_schema.global_variables
WHERE variable_name = 'innodb_log_file_size';


This will give you the size mysqld has. The default for MySQL 5.5 is 5M.

Whatever number that turns up should be placed in my.cnf. If it is not set, then place this

[mysqld]
innodb_log_file_size = (Whatever the filesize of ib_logfile0 is)


Try out xtrabackup after adding this to my.cnf.