It is wise to keep backups of your blog’s database, and wiser to keep those backups somewhere other than your blog’s server.
How I keep my backups is not a perfect plan, but it works for me. I keep a month’s worth of my backups in my Google Mail account.
Install a plugin (like WP-DBManager) that will automatically backs up your database and emails the backup file to your Google Mail account (Gmail.com or Google Apps for Domains) as an attachment. Go ahead and manually have the plugin send a backup to your email account – you need to test it anyway.
Check your email and open the email containing your backup file.
Copy the subject line.
Click the “More” button, then click “Filter messages like these”. The advanced search form will come up with the “From” field already filled out.
Paste the subject line into the Subject field.
Check the “Has attachment” box.
Click “Create filter with this search”
On the next screen, under “When a message arrives that matches this search:”, check the box “Delete it”.
Click “Create Filter” and you are done.
Why delete the backups as they come in? I am not permanently deleting them, just sending them to the Trash folder, and everything in the Trash folder that is older than 30 days is automatically permanently deleted. This saves me from needing to clean out the old backups myself.
One thing to remember is this does not back up the actual files on your site. A copy of the files on my sites is on my computer which is backed up using Crashplan.