Arguably, making the move from just a bunch of disks (JBOD) to a RAID like those I use from Drobo, is where to start? That’s simple. Answer this question: How much storage will be needed to house the data on all of those drives?

Label each drive with a number

Determining the space required means finding out how much space has been used on each drive. Begin with some masking tape. Put a strip on each drive. Now, number them starting with 1. Next, grab a sheet of paper or if you prefer make a spread sheet. List the number of each drive on the paper or spread sheet.

Get Info or Properties

Mount each drive on your computer. Highlight the drive then press Command + I on the Mac or Right Click on the Drive in Windows and choose Properties… Note the space used on Drive #1 and write it on your list or enter it on the spread sheet. Eject or remove the drive. Repeat for all of the remaining drives. Tally the capacities of each. Remember that a thousand gigabytes equals one terabyte. The total will be the starting place for creating a protected storage system.

JBOD discs numbered and labled with space used
“JBOD with 6 Drives” photo by Jamie Tuckeer

How much storage is needed?

The easy answer is more than the total space used in the numbered drives in the JBOD system. The six JBOD drives pictured above hold 12.58 terabytes of data. There’s 3.99 terabytes of space available. The solution is to copy each drive into a RAID (Redundant Array of Independent (or Inexpensive) Discs)) with more than 13 terabytes of capacity to hold all of the data plus space for at least a year’s worth of additional data. A RAID is a protected storage system.

Protected Storage

Protected storage means that if a single drive in the system fails, the system can recover the data and pass it back to a replacement drive. Some systems can offer dual disc redundancy, meaning that two drives can fail at the same time and the data is still safe. Data on a protected storage system is safer than on a single drive. A single drive in a JBOD system is not protected storage. When that drive fails, the data on it is lost.


A backup is a complete copy of the working storage system. In a JBOD system a backup is a copy of the working hard drive. Two backups of the working drive are needed for a 3-2-1 system. The same is true of a backup system using protected storage.

  • 3 copies
  • 2 on site one is the working drive and the other is a backup
  • 1 copy stored in an offsite location

JBOD v/s Protected Storage

JBOD is more expensive than protected storage. It is also very difficult to create backups. At some point the tangle of drives becomes so confusing that a backup plan becomes unmanageable. Imagine having to make two copies of each drive in a six JBOD array. TOO MUCH WORK!!! So much in fact, that people working with JBOD rarely if ever back them up. This leaves the data on each drive unprotected. Eventually each drive will fail. Absent a backup, when a drive dies, the data dies with it.

Protected storage seems to be more expensive than JBOD. It isn’t. It costs right at the same amount of money. RAIDs are available in several configurations although 5 drive bays are the most common. 5 bays, each filled with a 6 terabyte drive, can store 24 terabytes of data. That’s plenty of room for the 13 terabytes on the five drives shown along with more than adequate protected space for expansion. Remember that the equivalent of one drive is invested to provide the protection against the failure of any of the five drives. That’s why 5 bays times 6 terabyte drives equals 24 terabytes instead of the 30 terabytes in the RAID. A 5 bay entry level Drobo RAID costs $350.00. 5 drives each 6 terabytes in size cost about $250.00 each or $1,250.00. Add the enclosure for a total of $1,600.00. A JBOD system with 6 6tb drives costs around the same amount due to the cost of the enclosures for each hard drive. A solid enclosure for a 3.5 inch drive costs around $70.00 or (you’ve already done the math haven’t you?) $420.00

RAID v/s Beyond RAID

RAID devices require the same size drives be installed in each bay. The drives must be the same speed as well. Ideally, the drives would all be the same model number. Beyond RAID is a trademarked, patented system in all Drobo protected storage devices. These RAIDs are very versatile. The work with any size or speed of eSATA three and a half inch form factor hard drives. Drobos can be expanded to a 64terabyte volume by adding larger and larger hard drives. I have used Drobos for almost ten years now with no failures. Best of all, Drobo enclosure offer protected storage with only two drives on board.

Additional Protected Storage for Backups

There is still a need to backup the RAID. That means having two more units of protected storage. Is this expensive? Yes. Yes it is. It is completely cheap when compared to the cost in time, travel and money of producing those 13 terabytes of photographs. Protected storage can be phased in over time. I am not suggesting that they replace the backups. They absolutely do not. Protected storage guards against data loss due to a drive failure. Add the additional RAIDs as they can become affordable. Two backups with one offsite are as bulletproof as possible. Fail safe is a great concept. At this writing it’s not practically attainable.

For what it’s worth…

Summing up, 30 terabytes of unprotected JBOD costs the same as 24 terabytes of RAID protected storage. RAID, especially RAID from Drobo is a great investment that pays off not only in protection, it also provides great peace of mind. That’s priceless.

Photography: ©2016 Kevin Ames unless otherwise noted.