Why RAID Drive Protection is Not an Adequate Backup Strategy

RAID is the acronym for Redundant Array of Independent Disks. A RAID 1, RAID 5 or RAID 6 disk array, using two or more disk drives storing enough redundant information to permit continued operation through at least a single drive failure and subsequent rebuilding of a replacement drive, is a great image file and video storage option and I highly recommend implementing it. But, a RAID array featuring mirrored drives (RAID 1) or a parity drive (RAID 5) is not, alone, enough protection. Here are some reasons why:

1. RAID does not protect from inadvertent file deletion or other issues including undetected/accidental drag and drop. In a RAID system, all copies of data are immediately treated the same, with the redundant file and/or parity information being updated at the same time as the primary drive information. You will likely find yourself needing to retrieve a copy of a file from a backup more frequently than you will have the drive failures that RAID strategies protect against.
2. RAID does not protect from malicious viruses.
3. RAID does not protect from fire or other disasters.
4. RAID does not protect from theft or other intentional destruction.
5. RAID does not protect from data corruption. I have a long IT background and have multiple times lost servers due to RAID array corruption. While this should not happen, one of Bryan's Laws of Photography comes into play here: "If it can, it will."
6. RAID does not always protect from a second drive failure prior to recovery from an initial drive failure. While the odds of two drives failing within a short period of time may be low, drives in a RAID array are often aging at the same rate and influenced by the same factors including power and heat issues. A friend just lost 3 of 5 drives in a name brand RAID array due to a firmware/software issue.

Your RAID array must be backed up frequently and at least one current backup must be stored securely off-site. Look at what you have at stake (your entire image collection?) and implement a backup strategy that adequately protects those assets.

What are the backup options for a RAID array?

RAID array backup options include:

1. External hard drives including external RAID arrays
2. Network attached storage including network attached storage drives
3. LTO tape drives

There are online/internet backup options available for those fortunate enough to have adequate internet connection bandwidth, but if relying solely on an online service for your backup needs, you must have a great deal of trust in the company you are purchasing this service from. These companies can vanish at the throw of a switch. Also, make sure that some form of file archive access is provided to protect against inadvertent file deletions, etc. from being replicated to the service.