Redundancy:

For some, redundancy simply means having valuable information on a disk set aside for safe keeping. For others, it can mean adding a second connection to the internet, or a second set of servers to ensure everything is still accessible even if a server fails. There is a balance between what is important and what is necessary. It might be important for production to continue, but maybe not at the expense of having a complete duplication of the existing infrastructure and server systems. RAID (Redundant Array of Independent Disks) is a cheep and simple way to keep things going in the face of having a hard drive fail.

Choosing the right backup strategy is also important. The method and frequency of backing up data can very widely depending on your needs. Whether to include copies across the room, town, or country is also something to consider. This is not something that should be taken lightly.