Difference between revisions of "Site backup"

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Note: You are currently viewing documentation for Moodle 2.9. Up-to-date documentation for the latest stable version of Moodle may be available here: Site backup.

(See also: course backups)
(See also: delete link to updating)
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*[[Backup and restore FAQ]]
*[[Backup and restore FAQ]]
*[[Automated course backup]]
*[[Automated course backup]]
*The section "Backup important data" in [[Upgrading]]
*[http://www.moodletutorials.org/view_video.php?viewkey=e257e44aa9d5bade97ba Video showing how to backup a whole Moodle site (on Linux)]
*[http://www.moodletutorials.org/view_video.php?viewkey=e257e44aa9d5bade97ba Video showing how to backup a whole Moodle site (on Linux)]
* [[Moodle migration]]
* [[Moodle migration]]

Revision as of 18:49, 20 November 2010

A site backup allows a site administrator to save everything associated with a moodle site. These backups can be restored to bring a site back to the point in time when the backup was made.

Performing regular backups are highly recommended to reduce the amount of lost information in the event of a problem on the site and to speed the overall recovery process.

What needs to be backed up?

A Moodle system comprises three parts:

  1. The data stored in the database (For example, a MySQL database)
  2. The uploaded files (For example, site and course files uploaded via Moodle located in moodledata)
  3. The Moodle code (For example, everything in server/htdocs/moodle)

You can confirm where all these things are located in a Moodle installation by checking the config.php file.

  1. $CFG->dbna shows the database name
  2. $CFG->prefix shows the the database table name prefix
  3. $CFG->dataroot controls where the uploaded files are stored; and
  4. $CFG->dirroot points to where the code is stored.
Tip: Generally speaking, the database ("dbna and prefix") and the uploaded files (dataroot) are the two most important to copy on a regular basis. These contain information that will change most often. The Moodle code (dirroot) is less important as a frequent backup, since it will only change when the the actual code is changed through upgrades, addins and code tweaks.

Creating a backup of your Moodle site


The right way to back up your database depends on which database system you are using. The instructions below are one way to back up a MySQL database. Another option would be to use a tool like phpMyAdmin to manually make a backup. The documentation for your database will give more options.

There are many ways to do such backups. Here is an outline of a little script you can run on Unix to backup the database (it works well to have such a script run daily via a cron task):

cd /my/backup/directory
mv moodle-database.sql.gz moodle-database-old.sql.gz
mysqldump -h example.com -u myusername --password=mypassword -C -Q -e --create-options mydatabasename > moodle-database.sql
gzip moodle-database.sql

Character encoding

Make sure that a database backup uses the correct character encoding. In most databases, use UTF-8.

When dumping the entire Moodle database, check for possible character encoding issues. In some instances, backups created with mysqldump or phpMyAdmin may not properly encode all of the data. This will result in non-readable characters when the database is restored.

Tip: One solution is to use MySQL Administrator 1.1 or another tool that will force a UTF-8 dump of the data.

Tools for database backups

  • phpMyAdmin is the tool of choice with most web hosting providers.
  • MySQLDumper is a backup script for MySQL databases, written in PHP and Perl. MySQLDumper uses a proprietary technique to avoid execution interruption when running PHP scripts (the max. execution time is usually set to 30 seconds). MySQLDumper also cares for the encoding problems mentioned above. It also works with compressed files.

Uploaded files (moodledata)

Through the Moodle interface, users can upload or create files and folders. These are located in a directory, often called "moodledata". Since they are just files and folders, there are many different ways to backup or copy moodledata.

  • For example, using a file transfer program, copy the entire moodledata directory to a different area, drive or computer. Example of file transfer programs include: FTP, WinSP, wget, rsync.
  • You might use a compression program to create compact files (tar, zip. 7z, XZ, BZIP2, GZIP, and WIM are a few file formats) of the entire directory. This can be done before or after file transfers.
Tip: Typically not all moodledata files change between regular/periodic backups. A new Administrator might want to look into incremental or other efficient backups] procedures. Depending upon the operating environment there are [[Tools for backing up server files

|many tools]] and ways of backing up moodledata.

Moodle code

Backing up the Moodle code, will be similar to backing up moodledata. See Tools for backing up server files.

Tip: It is always a good idea to have several backup copies of your Moodle code files. While you can always download a fresh base copy of the Moodle code from download.moodle.org, you might have customized that code. It is a good idea to create a separate backup of your Moodle code before you customize the code. This includes installing Contributed code, Themes and upgrading.

Restoring a site backup

If you have followed the above instructions and created a backup of a Moodle site, you may need to know how to restore the site backup you created. Here is a set of basic steps that make up the restore process.

1. Rename the original Moodle directory to something different (so you still have it) and copy the backed up Moodle directory or a newly downloaded Moodle directory in its place.

2. If you are running MySQL, a backup of the database should be a .sql, .gz or .tar.gz file. If it is .tar.gz or .gz you need to extract it until it is an sql file.

tar -xzvf moodlesqlfile.tar.gz

3. If you are running mysql, import the SQL file back into a newly created database on the MySQL server. Be careful here, some backups try to import right back into the same working database that Moodle is connected to. This causes database problems that damage a Moodle installation. The best thing to do is make a new database, restore the backed up database into it, and change the Moodle config.php file to connect to this new database (this way you still have the original database).

Once you have created the new database:

mysql -p new_database < moodlesqlfile.sql

For other databases, follow their instructions for restoring a backup.

See also