Is backup redundancy necessary?

I recently had a practice ask me if replacing a failed backup drive was “necessary” to replace. Necessary is defined as “required to be done”. Synonyms listed by the Google search definition were “required”, “compulsory” and “imperative”. Now this was not their sole backup, this was one of the redundant backups. To be clear I’m talking about a redundant backup, not redundant data.

Data redundancy is different from backup data. Data redundancy usually comes in the form of RAID (Redundant Array of Independent Disks) configurations. Think of data redundancy as the backup parachute for a skydiver. When the part of the data array fails, there’s another element that will activate to maintain data integrity, just as the emergency chute protects the skydiver.

Data Redundancy is not as necessary as data backup for most circumstances. Data backup is basically keeping static copies of the data in multiple places. If your data is compromised you can restore the information to bring you to a point prior to the compromise or corruption.

The need for a backup usually is obvious. If you erase or remove data for whatever reason, a backup can restore that information. What may not be as obvious is the need for multiple backups. Backups are just as susceptible to problems as your original data. A second off site backup is also critical. If you have a catastrophic disaster at your server location, both your original data and any backups stored onsite could be destroyed.

A good rule of thumb is three backups. Two of these backups stored onsite and a third stored at a different location. This should statistically cover 99.99% of the disaster senarios a practice would encounter.

More backups add to data maintenance costs. But what many don’t consider how much will data loss cost. If a business has $100,000 in accounts receivable what will the loss of that data cost? Lost data reconstruction can cost thousands of dollars, if it’s even at all possible. A complete loss could cost that business $100,000.

So how did I answer the question, is the redundant backup “necessary”? Yes.