Displayed on the Plugin Manager as System - Backup on update
Joomla! 2.5 and later versions include the Joomla! Update component (originally developed as part of Admin Tools by our company, later donated to Joomla! and now maintained by the Joomla! team) which allows you to update Joomla! to its latest version. When you are updating between minor versions of Joomla! e.g. 3.2 to 3.3 or between major versions of Joomla! e.g. 2.5 to 3.x, some extensions on your site might experience problems or make your site inaccessible. It's always a good idea to take a backup of your site before upgrading Joomla!, but how many times did you forget to do it only to end up with an inaccessible site and a furious client? Our plugin is here to automate this process for you.
When this plugin is enabled it will "see" your attempt to update Joomla! and automatically launch Akeeba Backup to take a backup of your site. Once the backup is successfully complete it will take you back to Joomla! Update, allowing it to install the new Joomla! version. All this happens automatically. You and your clients can no longer forget to take a backup before updating Joomla!: the backup will be taken automatically.
Editing the plugin you will find the sole option, Backup Profile, which lets you define which Akeeba Backup profile to use for these automated backups. If you don't specify anything the default backup profile (the one with ID=1) will be used.
We recommend using a backup profile which stores a copy of the backup archive in external storage (e.g. Amazon S3, Dropbox or Box.com) on top of leaving a copy of the backup archive on your server. This way you have maximum protection against any kind of accidents caused by a failed or problematic Joomla! update.
When the plugin is enabled you will see an icon and a BoU label at the bottom of your site's administrator page, in the status area. You can temporarily disable (and re-enable) the backup on update feature by clicking on that icon.