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MySQL 9.4 Reference Manual  / ...  / The InnoDB Storage Engine  / InnoDB On-Disk Structures  / Tablespaces  /  Moving Tablespace Files While the Server is Offline

17.6.3.6 Moving Tablespace Files While the Server is Offline

Theinnodb_directories variable, which defines directories to scan at startup for tablespace files, supports moving or restoring tablespace files to a new location while the server is offline. During startup, discovered tablespace files are used instead those referenced in the data dictionary, and the data dictionary is updated to reference the relocated files. If duplicate tablespace files are discovered by the scan, startup fails with an error indicating that multiple files were found for the same tablespace ID.

The directories defined by theinnodb_data_home_dir,innodb_undo_directory, anddatadir variables are automatically appended to theinnodb_directories argument value. These directories are scanned at startup regardless of whether aninnodb_directories setting is specified explicitly. The implicit addition of these directories permits moving system tablespace files, the data directory, or undo tablespace files without configuring theinnodb_directories setting. However, settings must be updated when directories change. For example, after relocating the data directory, you must update the--datadir setting before restarting the server.

Theinnodb_directories variable can be specified in a startup command or MySQL option file. Quotes are used around the argument value because a semicolon (;) is interpreted as a special character by some command interpreters. (Unix shells treat it as a command terminator, for example.)

Startup command:

mysqld --innodb-directories="directory_path_1;directory_path_2"

MySQL option file:

[mysqld]innodb_directories="directory_path_1;directory_path_2"

The following procedure is applicable to moving individualfile-per-table andgeneral tablespace files,system tablespace files,undo tablespace files, or the data directory. Before moving files or directories, review the usage notes that follow.

  1. Stop the server.

  2. Move the tablespace files or directories to the desired location.

  3. Make the new directory known toInnoDB.

  4. Restart the server.

Usage Notes

  • Wildcard expressions cannot be used in theinnodb_directories argument value.

  • Theinnodb_directories scan also traverses subdirectories of specified directories. Duplicate directories and subdirectories are discarded from the list of directories to be scanned.

  • innodb_directories supports movingInnoDB tablespace files. Moving files that belong to a storage engine other thanInnoDB is not supported. This restriction also applies when moving the entire data directory.

  • innodb_directories supports renaming of tablespace files when moving files to a scanned directory. It also supports moving tablespaces files to other supported operating systems.

  • When moving tablespace files to a different operating system, ensure that tablespace file names do not include prohibited characters or characters with a special meaning on the destination system.

  • When moving a data directory from a Windows operating system to a Linux operating system, modify the binary log file paths in the binary log index file to use backward slashes instead of forward slashes. By default, the binary log index file has the same base name as the binary log file, with the extension '.index'. The location of the binary log index file is defined by--log-bin. The default location is the data directory.

  • If moving tablespace files to a different operating system introduces cross-platform replication, it is the database administrator's responsibility to ensure proper replication of DDL statements that contain platform-specific directories. Statements that permit specifying directories includeCREATE TABLE ... DATA DIRECTORY andCREATE TABLESPACE ... ADD DATAFILE.

  • Add the directories of file-per-table and general tablespaces created with an absolute path or in a location outside of the data directory to theinnodb_directories setting. Otherwise,InnoDB is not able to locate the files during recovery. For related information, seeTablespace Discovery During Crash Recovery.

    To view tablespace file locations, query the Information SchemaFILES table:

    mysql> SELECT TABLESPACE_NAME, FILE_NAME FROM INFORMATION_SCHEMA.FILES \G