InnoDB Startup Configuration When the  autoextend  attribute is specified, the data file automatically increases in size by 64MB increments as space is required. The  innodb_autoextend_increment  variable controls the increment size. To specify a maximum size for an auto-extending data file, use the  max  attribute following the autoextend  attribute. Use the  max  attribute only in cases where constraining disk usage is of critical importance. The following configuration permits  ibdata1  to grow to a limit of 500MB: [mysqld] innodb_data_file_path=ibdata1:12M:autoextend:max:500M A minimum file size is enforced for the  first  system tablespace data file to ensure that there is enough space for doublewrite buffer pages. The following table shows minimum file sizes for each  InnoDB  page size. The default  InnoDB  page size is 16384 (16KB). If your disk becomes full, you can add a data file on another disk. For instructions, see Resizing the System Tablespace. The size limit for individual files is determined by your operating system. You can set the file size to more than 4GB on operating systems that support large files. You can also use raw disk partitions as data files. See Using Raw Disk Partitions for the System Tablespace. InnoDB  is not aware of the file system maximum file size, so be cautious on file systems where the maximum file size is a small value such as 2GB. A trailing slash is required when specifying a value for  innodb_data_home_dir .  InnoDB  does not create directories, so ensure that the specified directory exists before you start the server. Also, ensure sure that the MySQL server has the proper access rights to create files in the directory. System tablespace files are created in the data directory by default ( datadir ). To specify an alternate location, use the  innodb_data_home_dir  option. For example, to create a system tablespace data file in a directory named  myibdata , use this configuration: [mysqld] innodb_data_home_dir = /myibdata/ innodb_data_file_path=ibdata1:50M:autoextend InnoDB  forms the directory path for each data file by textually concatenating the value of innodb_data_home_dir  to the data file name. If  innodb_data_home_dir  is not defined, the default value is “./” , which is the data directory. (The MySQL server changes its current working directory to the data directory when it begins executing.) Alternatively, you can specify an absolute path for system tablespace data files. The following configuration is equivalent to the preceding one: [mysqld] innodb_data_file_path=/myibdata/ibdata1:50M:autoextend When you specify an absolute path for  innodb_data_file_path , the setting is not concatenated with the  innodb_data_home_dir  setting. System tablespace files are created in the specified absolute path. The specified directory must exist before you start the server. 3105 Page Size (innodb_page_size) Minimum File Size 16384 (16KB) or less 3MB 32768 (32KB) 6MB 65536 (64KB) 12MB