(mysql.info.gz) InnoDB Raw Devices

Info Catalog

(mysql.info.gz) InnoDB Disk I/O

(mysql.info.gz) File space management

(mysql.info.gz) InnoDB File space

 
 15.15.2 Using Raw Devices for the Tablespace
 --------------------------------------------
 
 Starting from MySQL 3.23.41, you can use raw disk partitions as
 tablespace data files.  By using a raw disk, you can perform
 non-buffered I/O on Windows and on some Unix systems without filesystem
 overhead, which might improve performance.
 
 When you create a new data file, you must put the keyword `newraw'
 immediately after the data file size in `innodb_data_file_path'.  The
 partition must be at least as large as the size that you specify.  Note
 that 1MB in `InnoDB' is 1024 * 1024 bytes, whereas 1MB usually means
 1,000,000 bytes in disk specifications.
 
      [mysqld]
      innodb_data_home_dir=
      innodb_data_file_path=/dev/hdd1:3Gnewraw;/dev/hdd2:2Gnewraw
 
 The next time you start the server, `InnoDB' notices the `newraw'
 keyword and initializes the new partition. However, do not create or
 change any `InnoDB' tables yet. Otherwise, when you next restart the
 server, `InnoDB' will reinitialize the partition and your changes will
 be lost.  (Starting from 3.23.44, as a safety measure `InnoDB' prevents
 users from modifying data when any partition with `newraw' is
 specified.)
 
 After `InnoDB' has initialized the new partition, stop the server,
 change `newraw' in the data file specification to `raw':
 
      [mysqld]
      innodb_data_home_dir=
      innodb_data_file_path=/dev/hdd1:5Graw;/dev/hdd2:2Graw
 
 Then restart the server and `InnoDB' will allow changes to be made.
 
 On Windows, starting from 4.1.1, you can allocate a disk partition as a
 data file like this:
 
      [mysqld]
      innodb_data_home_dir=
      innodb_data_file_path=//./D::10Gnewraw
 
 The `//./' corresponds to the Windows syntax of `\\.\' for accessing
 physical drives.
 
 When you use raw disk partitions, be sure that they have permissions
 that allow read and write access by the account used for running the
 MySQL server.
 

Info Catalog

(mysql.info.gz) InnoDB Disk I/O

(mysql.info.gz) File space management

(mysql.info.gz) InnoDB File space