Manual:Restoring a wiki from backup

One should backup one's wiki regularly, even if one never needs to restore it: backups provide peace of mind. However, a backup is useless if one cannot restore, and practice restoring a backup prevents later anguish. Hence, these instructions.

Versions and upgrading
The instructions on this page should apply more or less evenly to any given version of MediaWiki. However, avoid upgrading MediaWiki or its database schema prior to restoring! Particularly, avoid restoring a database backup from an older version of the software into a newer version; this will not work.

Overview

 * 1) Re-create the database, user and permissions
 * 2) Import the database backup
 * 3) Import the MediaWiki files
 * 4) Check the configuration file
 * 5) Test

Re-create the database, user and permissions
On the server on which you are restoring MediaWiki, ensure you have


 * 1) a correctly-working instance of MySQL
 * 2) a user with appropriate permissions

If you are restoring from backup due to database corruption, consider reinstalling MySQL! Once MySQL is working properly, create a new MySQL database and grant your user account permissions on the database. SELECT, INSERT, UPDATE and DELETE permissions should suffice. You may need to consult the MySQL documentation, your hosting provider's control panel documentation, or the documentation of any other utilities you are using for information on how to do this.

Note: It doesn't matter if the database doesn't have the same name; indeed, in a commercial hosting environment, where database names are usually prefixed with a hosting account username, a different database name is almost guaranteed. In addition, the username can differ, as can that user's password. You will have to adjust the LocalSettings.php file on the new location accordingly.

Import the database backup
Next, import your database backup. This will create the tables in the database and populate them with data. Importing takes a variable amount of time, depending upon the number of pages, users, edits, etc. in your wiki.

From the command line using mysql
If a database exists and you want to entirely replace it from the backup. To destroy the database: mysqladmin -u userid -ppassword drop wikidbname Substituting as apropriate for userid password and wikidbname Then to create a new database: mysqladmin -u userid -ppassword create wikidbname

For example after backing up with mysqldump, eg. mysqldump --default-character-set=binary --user=foobar --password=barbaz wikidb > dbdump.txt Make sure to specify the correct character set or the restore may fail, check LocalSettings.php to find out which it is.

Note: After using using mysqldump, you can't just use mysqlimport. Mysqlimport requires the data to be loaded in some delimited text format, eg. CSV, whereas the output of mysqldump is a sequence of SQL statements.

To import dbdump.txt from the command line do: and afterwards do:

To wipe and restore the wiki file system
Remember to also restore the file system components of the wiki that might be required, eg. images, logo, and extensions. Especially to edit LocalSettings.php to check everything is correct. A sequence of Linux commands to wipe and restore the wiki file system could look like this: wget http://download.wikimedia.org/mediawiki/1.20/mediawiki-1.20.2.tar.gz tar -xpzf mediawiki-1.20.2.tar.gz rm mediawiki-1.20.2.tar.gz rm -fR wiki_folder/ mv mediawiki-1.20.2 wiki_folder rm -fR wiki_folder/extensions/ cp -R backup/extensions wiki_folder/extensions

Open the wiki from the browser and click on the Set up the wiki first link. After this is done edit LocalSettings.php to suit the fresh install, restoring lines for extensions, etc. Restore from backup any other files, such as a custom logo and favicon to the correct paths.

If you've not installed as a root user and the images and thumbnails don't work, you'll need to chmod 777 wiki_folder/images this creates a security risk, so add  to the wiki folders .htaccess file, to prevent folder browsing.

See also Executing SQL Statements from a Text File

With the browser for phpMyAdmin
Open the browser to your phpadmin link, login, choose the wiki database. (Check LocalSettings.php if you're not sure). Select Structure, localhost, Your_Table. Select CheckAll. From the drop down select Drop, then Ok to wipe the old table. Click on Import, select Browse, pick your uncompressed plain text SQL file and import it. Press Go.

Remember to also restore file system components of the wiki that might be required, eg. images, logo, and extensions, (see above under mysql).

From an xml dump
To import an XML dump into a wiki, use the command-line tool importDump.php.

Import the MediaWiki files
Next, restore your backup of the MediaWiki filesystem: this is the final "large" step in the restore process. If you followed the backup manual instructions, and backed up the entire directory, this will include the images and extensions directories, plus custom skins, etc. and the configuration file. If you backed up only portions of the directory, e.g. images, extensions, etc. then you will need to first upload/copy a fresh install of the MediaWiki files, then transfer the backed-up directories and files into the correct locations in the new filesystem.

Check the configuration file
The final task involves verification of, and possibly modifying, the LocalSettings.php file. If you are restoring onto the same server from which you backed up, you probably need not change anything. If you are restoring onto a new server (i.e., if you are moving or duplicating the MediaWiki), certain entries will almost undoubtedly require changing, and you may need to change the database connection information as well.

Check the following configuration options:

You might also need to check the paths to diff3, ImageMagick, etc.

Test
At this point, attempt to access the wiki on the new server and use it. Log in as a sysop and a regular user and check that viewing, creating and editing pages and uploading files still works. You will need to fix any problems reported either by PHP or MediaWiki itself.