Difference between revisions of "Wiki Backup"
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Latest revision as of 14:27, 9 May 2016
It is important to make regular backups of the data in your wiki. This page provides an overview of the backup process for a typical MediaWiki wiki; you will probably want to devise your own backup scripts or schedule to suit the size of your wiki and your individual needs.
Overview
MediaWiki stores important data in two places:
- Database
- Pages and their contents, users and their preferences, metadata, search index, etc.
- File system
- Software configuration files, custom skins, extensions, images (including deleted images), etc.
Consider making the wiki read-only before creating the backup - see <tvar|readOnly>$wgReadOnly</>. This makes sure all parts of your backup are consistent (some of your installed extensions may write data nonetheless).
File transfer
You will have to choose a method for transferring files from the server where they are:
- Non-private data you can simply publish on archive.org and/or in a
dumps/directory of your webserver. - SCP (or WinSCP), SFTP/FTP or whatever other transfer protocol you're used to/is available.
- The hosting company might provide a file manager interface via a web browser; check with your provider.
Database
Most of the critical data in the wiki is stored in the database, which is typically straightforward to back up. When using the default MySQL backend, the database can be dumped into a script file which can be used later to recreate the database and all the data in it from scratch.
MySQL
Mysqldump from the command line
The most convenient way to create a dump file of the database you want to back up is to use the standard MySQL dump tool mysqldump from the command line. Be sure to get the parameters right or you may have difficulty restoring the database. Depending on database size, mysqldump could take a considerable amount of time.
First insert the following line into LocalSettings.php </translate>
$wgReadOnly = 'Dumping Database, Access will be restored shortly';
<translate> this can be removed as soon as the dump is completed.
Example of the command to run on the Linux/UNIX shell: </translate>
mysqldump -h hostname -u userid --password --default-character-set=whatever dbname > backup.sql
<translate> Substituting hostname, userid, character-set, and dbname as appropriate. mysqldump will prompt for the password. If no character set is specified, mysqldump x.x.xTemplate:Clarify uses utf8, and earlier versions used latin1. Your wiki's database might be using binary. Check in the LocalSettings.php file to find out which (usually under $wgDBTableOptions DEFAULT CHARSET). Otherwise mysql might dump according to the server's file system and not the wiki's. The dbname can also be found in LocalSettings.php under $wgDBname.
See mysqldump for a full list of command line parameters.
The output from mysqldump can instead be piped to gzip, for a smaller output file, as follows </translate>
mysqldump -h hostname -u userid --password dbname | gzip > backup.sql.gz
<translate>
A similar mysqldump command can be used to produce xml output instead, by including the --xml parameter. </translate>
mysqldump -h hostname -u userid --password --xml dbname > backup.xml
<translate> and to compress the file with a pipe to gzip </translate>
mysqldump -h hostname -u userid --password --xml dbname | gzip > backup.xml.gz
<translate>
Remember to also backup the file system components of the wiki that might be required, eg. images, logo, and extensions.
Running mysqldump with Cron
Cron is the time-based job scheduler in Unix-like computer operating systems. Cron enables users to schedule jobs (commands or shell scripts) to run periodically at certain times or dates.
A sample command that you may run from a crontab may look like this: </translate>
nice -n 19 mysqldump -u $USER --password=$PASSWORD $DATABASE -c | nice -n 19 gzip -9 > ~/backup/wiki-$DATABASE-$(date '+%Y%m%d').sql.gz
<translate>
The nice -n 19 lowers the priority of the process.
Use valid values for $USER, $PASSWORD, and $DATABASE. This will write a backup file with the weekday in the filename so you would have a rolling set of backups. If you want to save the files and extensions as well, you might want to use this one.
</translate>
Template:Warning
<translate>
If you want to add this task in Cron through Cpanel then you must escape the character "%"
</translate>
/usr/bin/mysqldump -u $USER --password=$PASSWORD $DATABASE -c | /bin/gzip > ~/backup/wiki-$DATABASE-$(date '+\%Y\%m\%d').sql.gz
<translate>
or you will get an error: </translate>
/bin/sh: -c: line 0: unexpected EOF while looking for matching `'' /bin/sh: -c: line 1: syntax error: unexpected end of file
<translate>
Tables
Under close examination one finds that some of the [[<tvar|layout>Special:MyLanguage/Manual:Database layout</>|tables]] dumped have various degrees of temporariness. So to save disk space (beyond just gziping), although those tables need to be present in a proper dump, their data does not. However, under certain circumstances the disadvantage of having to rebuild all this data may outweigh the saving in disk space (for example, on a large wiki where restoration speed is paramount).
See mailing list thread mysql5 binary schema about the topic.
Latin-1 to UTF-8 conversion
See the [[<tvar|upgrading>Special:MyLanguage/Manual:Upgrading#How do I upgrade from a really old version? In one step, or in several steps?</>|relevant section of the upgrading page]] for information about this process. Also see the [[<tvar|talk>Manual talk:Backing up a wiki</>|talk page]] for more information about working with character sets in general.
PostgreSQL
You can use the pg_dump tool to back up a MediaWiki PostgreSQL database. For example:
</translate>
pg_dump mywiki > mywikidump.sql
<translate>
will dump the mywiki database to mywikidump.sql.
To restore the dump: </translate>
psql mywiki -f mywikidump.sql
<translate>
You may also want to dump the global information, e.g. the database users:
</translate>
pg_dumpall --globals > postgres_globals.sql
<translate>
SQLite
</translate>
<translate>
phpMyAdmin
Turn your wiki to read only by adding $wgReadOnly = 'Site Maintenance'; to LocalSettings.php.
Open the browser to your phpadmin link, login, choose the wiki database. (Check LocalSettings.php if you're not sure). Select Export. Make sure all items under Export are highlighted, and make sure Structure is highlighted (it's important to maintain the table structure). Optionally check Add DROP TABLE to delete existing references when importing. Make sure Data is checked. Select zipped. Then click on GO and save the backup file.<ref>[[<tvar|talk>Manual_talk:Backing_up_a_wiki#Ubuntu_10.10_-_Step_by_Step_Instructions</>|Manual_talk:Backing_up_a_wiki#Ubuntu_10.10_-_Step_by_Step_Instructions]]</ref>
Remove $wgReadOnly = 'Site Maintenance'; from LocalSettings.php
Remember to also backup the file system components of the wiki that might be required, eg. images, logo, and extensions.
External links
- For a tutorial, see Siteground: MySQL Export: How to backup a MySQL database using phpMyAdmin
- Backing up the Database
HeidiSQL
HeidiSQL is similar to phpMyAdmin, but without any restrictions of phpMyAdmin's free version.
File system
MediaWiki stores other components of the wiki in the file system where this is more appropriate than insertion into the database, for example, site configuration files ([[<tvar|localSettings>Special:MyLanguage/Manual:LocalSettings.php</>|LocalSettings.php]], [[<tvar|adminSettings>Special:MyLanguage/Manual:AdminSettings.php</>|AdminSettings.php]]), image files (including deleted images, thumbnails and rendered math and SVG images, if applicable), skin customisations, extension files, etc.
The best method to back these up is to place them into an archive file, such as a .tar file, which can then be compressed if desired. On Windows, applications such as WinZip or 7-zip can be used if preferred.
For Linux variants, assuming the wiki is stored in /srv/www/htdocs/wiki </translate>
tar zcvhf wikidata.tgz /srv/www/htdocs/wiki
<translate> It should be possible to backup the entire "wiki" folder in "htdocs" if using XAMPP.
Backup the content of the wiki (XML dump)
It is also a good idea to create an XML dump in addition to the database dump. XML dumps contain the content of the wiki (wiki pages with all their revisions), without the site-related data (they do not contain user accounts, image metadata, logs, etc).<ref>XML dumps are independent of the database structure, and can be imported into future (and even past) versions of MediaWiki.</ref>
XML dumps are less likely to cause problems with character encoding, as a means of transfering large amounts of content quickly, and are easily be used by third party tools, which makes XML dumps a good fallback should your main database dump become unusable.
To create an XML dump, use the command-line tool [[<tvar|dumpBackup>Special:MyLanguage/Manual:dumpBackup.php</>|dumpBackup.php]], located in the maintenance directory of your MediaWiki installation. See [[<tvar|dumpBackup2>Special:MyLanguage/Manual:dumpBackup.php</>|Manual:dumpBackup.php]] for more details.
You can also create an XML dump for a specific set of pages online, using Special:Export, although attempting to dump large quantities of pages through this interface will usually time out.
To import an XML dump into a wiki, use the command-line tool [[<tvar|importDump>Special:MyLanguage/Manual:importDump.php</>|importDump.php]]. For a small set of pages, you can also use the Special:Import page via your browser (by default, this is restricted to the sysop group). As an alternative to dumpBackup.php and importDump.php, you can use MWDumper, which is faster, but requires a Java runtime environment.
See [[<tvar|import>Special:MyLanguage/Manual:Importing XML dumps</>|Manual:Importing XML dumps]] for more information.
Without shell access to the server
If you have no shell access, then use the WikiTeam Python script dumpgenerator.py from a DOS, Unix or Linux command-line. To run the script see the WikiTeam tutorial.
See also Meta:Data dumps.
Scripts
</translate> Template:Warning <translate>
- [[<tvar|script>Special:MyLanguage/Manual:Backing up a wiki/Duesentrieb's backup script</>|Unofficial backup script]] by User:Duesentrieb.
- Unofficial backup script by Flominator; creates a backup of all files and the database, with optional backup rotation.
- User:Darizotas/MediaWiki Backup Script for Windows - a script for backing up a Windows MediaWiki install. Note: Has no restore feature.
- Unofficial web-based backup script, mw_tools, by Wanglong (allwiki.com); you can use it to back up your database, or use the backup files to recover the database, the operation is very easy.
- WikiTeam tools - if you do not have server access (e.g. your wiki is in a free wikifarm), you can generate an XML dump and an image dump using WikiTeam tools (see some saved wikis)
- Another backup script that: dumps DB, files, and XML; puts the site into read-only mode; timestamps backups; and reads the charset from LocalSettings. Script does not need to be modified for each site to be backed up. Does not (yet) rotate old backups. Usage:
backup.sh -d backup/directory -w installation/directory
- Script to make periodical backups mw_backup. This script will make daily, weekly and monthly backups of your database and images directory when run as a daily cron job.
