Are you looking to have the folders mirrored every hour or do you want multiple snapshots, each being a particular hour?
I'm assuming you'd want to mirror to the external drive. In that case I'd take a look at rsync and cron.
rsync will allow you to backup/mirror with any options you want. It really is quite powerful. Assuming you have the drive mounted at /mnt/share the command would look like this
Code:
rsync -uav /home/user/folder /mnt/share/folder
cron can run this every hour for you, check out the crontab man pages. It's not as difficult as it first looks...
Linear Mode
