How do I (automatically) backup my Time Capsule?
I'm worried that I will lose important data like photo's and video's when the harddrive of my Time Capsule crashes.
Apple does not provide an automatic function for this.
You can manually Use Airport Utility and its "archive disk" function to make a snapshot copy of the current Time Capsule drive to an external disk connected directly into the Time Capsule's USB port.
This can take several hours. But if your time capsule dies then you could copy these files back to a new Time Capsule or a repaired Time Capsule.
The only way you can back up a Time Machine disk is to create a disk image, as TM uses special hard links to backup differential items.
You can add another disk to your Time Machine preferences. OS X will then back up to each one, switching every hour (i.e. 1:00: HD, 2:00: TC, 3:00: HD, 4:00: TC, etc...). It's very easy: http://www.maintain.se/blog/backing-up-to-multiple-time-machine-drives/