# Drobo 5C Review

December 11, 2016
By

When the digital revolution arrived to photography, one of the side-effects was a demand for enterprise class storage even by the most amateur of photographers. Every digital photography course ever offered has always hammered this point:

Always use the best quality storage devices and always make sure you have two backups.

Some have gone so far as to add a third off-site backup. The issue here is that the larger the storage device, the greater it’s cost. Large, well funded companies can afford mega-sized drives, but how do the smaller guys do it? Coming from an information technology background, I can tell you that we ran into this issue ages ago. The answer was something called RAID. RAID is actually an acronym which stands for Redundant Array of Inexpensive Drives and it is a technology that allows you to group multiple smaller drives together to present themselves as a single, larger drive. RAID has multiple methods for performing this little feat, but the most common one is called block-level striping with distributed parity or RAID 5.

### What’s so great about that?

Well for one thing, it allows you to, as previously mentioned, gang smaller drives together and have them behave a single, larger drive. It also provides protection in case a drive fails by backing up an individual drive’s data onto all of the other drives. Should a drive fail, the RAID 5 Array will continue to function and when the failed drive is replaced, and it can automatically repopulate the new drive with the data of the failed drive including any changes to the data that have occurred since the drive failed. What if two drives fail? Well with RAID 5, you are pretty much hosed.

In the case of wanting to protect against the simultaneous failure of two drives, RAID 6 (block-level striping with double distributed parity) should be used as this maintains two parity stripes and can handle two simultaneously failed drives.

Both RAID levels 5 and 6 allow for improved read performance as read requests are distributed over all of the drives. The more drives in the array, the faster the read speeds.

### Sounds great! Is there a downside?

All is not beer and skittles in the land of RAID. There are certain penalties to be paid for these levels of speed and data protection. First off, any RAID array requires that all drives in the array be of the same size. Add a 4TB drive to an array of 2TB drives and only 2TB of the larger drive will be used. Setup of the array is a long process with striping of large drives taking up to 24 hours. With RAID 5, a minimum of three (3) drives are required to create the array. With RAID 6, a minimum of four (4) drives are needed. There is a storage cost as well: RAID 5 has a space efficiency formula of:

$1-\frac{1}{n}$

Whereas RAID-6 has a space efficiency formula of:

$1-\frac{2}{n}$

What these formulas mean is that the space cost of the levels of data protection provided by RAIDs 5 and 6 are dependent on the number of drives involved. For example: if you have a RAID array of 5 x 2TB drives, a RAID 5 configuration would leave you with 80% of the total space available for use and a RAID 6 would leave you with 60% available (8TB and 6TB respectively in our 5 x 2TB array).

On top of that, RAID arrays require battery backups so that, in case of power failure, they can complete any writes they have pending.

### Enter Drobo

In June 2007, Drobo Inc. (then called Data Robotics, Inc.) introduced their line of storage devices which promised RAID-like storage without some of the downsides of traditional RAID arrays. All Drobo devices (including the 5C I was sent for review) can pool different sized drives together and still provide data protection. Using a technology called BeyondRAID, Drobo devices can quickly and simply allow you to set up a pooled storage array using any drives you happen to have on hand.

Like a traditional RAID array, some of the storage space is sacrificed for the sake of data protection. Since the Drobo can sport drives of varying sizes, you will lose the space roughly equivalent to the largest drive installed in the array. More so if you select dual drive redundancy (a feature that mimics RAID 6 in the number of drives protected from failure).

There are various models of the Drobo, with some of the Pro models supporting up to 12 drives. The latest is the Drobo 5C, a 5-bay device which uses a SuperSpeed USB 3.1 port to provide extremely fast, locally attached storage. Unlike the 5N or Pro models, the 5C does not contain a built-in Ethernet port and cannot run as a standalone device. However, the use of a USB-C 3.1 port makes it compatible with PCs and Macs.