This post is mainly an aggregation of ressources found there and there on the web in order save a MySQL database on a regular time basis, making the dumps available in a network shared folder.

Setup :

This article was written for a RaspberryPI with a Raspbian and a MySQL server. The steps should be the same for other Linux distributions.

MySQL user

First, we will create a mysql user wich only privileges will be to read the db:

On the raspberry pi, type:

• mysql -uroot -p to log in Mysql as root (password will be prompted).
• On the MySQL prompt : GRANT LOCK TABLES, SELECT ON DATABASE.* TO 'BACKUPUSER'@'%' IDENTIFIED BY 'PASSWORD'; to create the user BACKUPUSER with password PASSWORD with privileges on all tables in DATABASE. You can replace DATABASE with * to grant privileges on all dbs.
• Then flush the privileges with flush privileges;.
• You can now log out with exit;

The Cron task (Source)

First, create the folder where the dumps will be saved:

• sudo mkdir /var/db_dumps

The task will be created on the current Raspberry, so this will be a local task:

• Edit /etc/crontab with your favorite editor and add the following: 0 * * * * USER /usr/bin/mysqldump DATABASE -uBACKUPUSER -pPASSWORD > /var/db_dumps/filename.sql. If you plan to backup all your databases, replace DATABASE by --all-databases. USER is the a system user
• If you want to have the date in your file name, use something like filename_`date +\%Y\%m\%d_\%H\%M`.sql (Source]
• To help you creating the cron job, you can use the Crontab-generator

Setting up Samba share

For the files to be available on the network, i'll use Samba.

• Install Samba with sudo apt-get install samba
• Edit file /etc/samba/smb.conf
• Add the following at the end of the file (got help from this):

[DbDumps]
  comment=Dumps of the MySQL server
  path=/var/db_dumps/
  browseable=yes
  read only=yes
  guest ok=yes
  public=yes

That's it...

Following this, your database will be saved every hour on a publicly read-only folder on your network. To go further, you can disable other shares in /etc/samba/smb.conf if you don't need it