17.20.1 Troubleshooting InnoDB I/O Problems

The troubleshooting steps for InnoDB I/O problems depend on when the problem occurs: during startup of the MySQL server, or during normal operations when a DML or DDL statement fails due to problems at the file system level.

Initialization Problems

If something goes wrong when InnoDB attempts to initialize its tablespace or its log files, delete all files created by InnoDB: all ibdata files and all redo log files (#ib_redoN files). If you created any InnoDB tables, also delete any .ibd files from the MySQL database directories. Then try initializing InnoDB again. For easiest troubleshooting, start the MySQL server from a command prompt so that you see what is happening.

Runtime Problems

If InnoDB prints an operating system error during a file operation, usually the problem has one of the following solutions:

• Make sure the InnoDB data file directory and the InnoDB log directory exist.

• Make sure mysqld has access rights to create files in those directories.

• Make sure mysqld can read the proper my.cnf or my.ini option file, so that it starts with the options that you specified.

• Make sure the disk is not full and you are not exceeding any disk quota.

• Make sure that the names you specify for subdirectories and data files do not clash.

• Doublecheck the syntax of the innodb_data_home_dir and innodb_data_file_path values. In particular, any MAX value in the innodb_data_file_path option is a hard limit, and exceeding that limit causes a fatal error.