I have three Pis running in my local net and backup them on a regular base.
I just detected threads where people asked how to create a backup just in case something went wrong. I tried to answer in the threads - but I don't have enough credits to do so :-(
That's why I just post a link to a backup script which I use to backup my Pis. It's able to create dd, tar and rsync backups and to restore them. It's used by a lot of people already - primarily by German folks. Hope it's useful also for others :-) raspibackup - Raspberry creates backups of itself