Back Up a Step
Backups are your next line of defense after high availability options like resilience and redundancy. As described in Chapter 4, you can protect against failure to a degree. While hardware failure does happen and disasters, like sheep, do happen, the main cause of unavailability of a system is maintenance that has gone wrong. Backups are always necessary no matter how comprehensive your resilience and redundancy planning because data on a disk is fragile and any number of things can destroy it. However, one of the principle advantages of digital data over physical data is that it is relatively easy to create an exact copy. Content that is simply zeros and ones can be copied with almost perfect fidelity whereas copying a physical document is a process far more prone to error. You’ll rarely regret making copies of data.
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