RAID Backup


Today’s Question: I recently realized that, although I had a backup copy of the external drive where I store my images, the drives were at least three years old. Since I recently read a scary article on the failure rates of various brands of drives within five years, I decided that I should replace the drives. Rather than buy two new separate external drives, I decided to buy an enclosure for two 4TB internal drives that are mirrored using a RAID setting. In this way, any changes in one drive are mirrored to the other. My question is whether you would consider this to be an acceptable way of maintaining a backup of the images from the time of download. I should add that in addition, I also use Goodsynch to back up the mirrored drives and I use Backblaze as an offsite, online backup. I’d appreciate your opinion as to whether you think this is an adequate process.

Tim’s Quick Answer: Using a drive with RAID mirroring is better than using a single hard drive, but not as good (in terms of backup security) as backing up to a second hard drive immediately. With this approach, my (admittedly paranoid) preference would be to not format the media card in the camera until another backup to a separate physical device is performed.

More Detail: There are, of course, many possible solutions for backing up your photos, and from my perspective there isn’t a single “right” solution. Instead, there are a variety of options, and those options fall on a scale between what I would consider “high risk” and “low risk”.

The highest risk approach, of course, is to never backup your photos at all. From there you can define a wide variety of workflows for backing up your photos that offer various degrees of protection.

My concern about a RAID mirroring solution is that both copies of your data are stored on a single physical device. Granted, there are two actual hard drives, but those two hard drives are connected to the same power supply and data connection, and are also contained in the same enclosure. In other words, if something happens to the overall device, you could lose both copies of your photos at one time.

This issue is mitigated, of course, by creating additional copies of your photos via a synchronization backup and an online backup, in your particular example. That obviously creates a situation where you ultimately have four copies (including the originals) of your photos even after you’ve formatted the digital media card in your camera.

My concern in this case relates to the time between downloading your photos to the RAID hard drive and creating an additional backup on a separate physical device (such as via synchronization), especially if you are going to immediately format the card in the camera to use for new captures.

In other words, with this type of setup my personal preference would be to download to the RAID drive (creating a master and backup copy in the process), but then to wait until after another backup is created on a separate physical device to format the media card in the camera.

As always, a backup workflow involves making decisions that balance security versus workflow efficiency. My preference whenever possible is to take the most conservative approach possible that is still reasonably easy to implement.

It is worth noting, for example, that on many trips I have two copies of my photos stored on two separate hard drives, but I still often have both of those hard drives in the same camera bag. That involves a certain degree of risk, so it is important to maintain a degree of perspective here. When it comes to backing up your photos, there is always an even more paranoid step you could add to your workflow!