Drobo Mini rocks storage and speed in a small package

Take the ever-expanding storage capabilities of Drobo BeyondRAID storage, throw in some Thunderbolt, and put it all into a small box and what do you have? Drobo Mini (US$649 MSRP, available for much less online).

To pack a lot of RAID-protected storage in a small space, Drobo chose to use 2.5" SATA laptop drives as the standard. There are four bays for drives in the Drobo Mini -- it comes empty, and you add drives of any capacity to fill 'em up. You can mix and match capacities, or even drop 2.5" SATA SSD or hybrid drives into the box for more speed. At this point, those 2.5" drives only come in capacities up to 1 TB, but as capacities increase in the future you'll be able to easily hot swap the "old" drives for more storage.

The Drobo Mini won't take up a lot of room on your desktop, unlike its larger siblings. Size-wise, it's 7.3" wide x 1.8 " tall x 7.1" deep (187.2 mm x 44.6 mm x 180.0 mm), and weighs 2.2 lbs (1 kg) without the power supply and drives.

As with the Drobo 5D I tested last month, the Drobo Mini comes with a separate slot on the bottom in which an optional mSATA SSD drive can be installed. The company calls it the Accelerator Bay, and the test device came without that drive installed.

About the pricing: although the suggested retail price of the Drobo Mini is $649, it was available a few days ago on Amazon for just $318.99.


Setup of the Drobo Mini is incredibly simple. If you already have the Drobo Dashboard software installed on your Mac, you simply unpack the drive, remove the front door, slide in your drives, close the door, plug in the Thunderbolt or USB 3.0 cable and power, and then turn it on. After a quick format of the drive array, you're ready to roll. That entire process, including the formatting, took me about four minutes.

The four drives I installed were 1 TB WD "Blue" drives. Set up with single disk redundancy (one drive can totally fail and be rebuilt without compromising the array), that provided 2.72 TB of storage with .91 TB used for protection of the array and 4.88 GB taken up for overhead. If I had set that up with dual disk redundancy (two drives can fail, be replaced, and be rebuilt without problems), I would have 1.81 TB of storage, 1.82 TB being used for array protection, and 3.25 GB chewed up for overhead.

The device has two Thunderbolt connectors, but can also be used with USB 3.0. Cables are included in the box, so it's literally a plug-and-play storage solution. The two Thunderbolt ports are perfect if you wish to daisy-chain Drobo Minis and add in a couple of monitors.


Benchmarking of the Drobo Mini was done with Intech Software's SpeedTools QuickBench 4.0 software. To ensure accuracy in testing, I performed a 100-cycle complete test. This subjects the drive to sequential and random read and write tests with file sizes from 4K to 100 MB, then graphically or textually displays that information to show the "sweet spots" for a specific drive or array. For example, if your work involves shuffling around a lot of very large files, you'll probably want a drive that has peak read/write speeds for files around your average file size.

The tests were performed both with Thunderbolt and USB 3.0. Using Thunderbolt, the standard test results (nine different file sizes between 4 KB and 1024 KB) showed average speeds as follows:

  • Sequential Read: 95.734 MB/Sec (140.504 MB/Sec for Drobo 5D)

  • Sequential Write: 92.657 MB/Sec (93.245 MB/Sec for Drobo 5D)

  • Random Read: 86.858 MB/Sec (116.435 MB/Sec for Drobo 5D)

  • Random Write: 63.816 MB/Sec (70.410 MB/Sec for Drobo 5D)

For the large test -- transfer sizes between 2 and 10 MB -- the average results were:

  • Large Read: 242.674 MB/Sec (341.327 MB/Sec for Drobo 5D)

  • Large Write: 283.218 MB/Sec (282.060 MB/Sec for Drobo 5D)

And for the extended test -- transfer sizes between 20 and 100 MB -- the average results were:

  • Extended Read: 198.521 MB/Sec (255.953 MB/Sec for Drobo 5D)

  • Extended Write 207.001 MB/Sec (262.864 MB/Sec for Drobo 5D)

For USB 3.0, the results were

  • Sequential Read: 72.593 MB/Sec (99.533 MB/Sec for Drobo 5D)

  • Sequential Write: 112.456 MB/Sec (111.509 MB/Sec for Drobo 5D)

  • Random Read: 62.968 MB/Sec (94.895 MB/Sec for Drobo 5D)

  • Random Write: 70.996 MB/Sec (80.605 MB/Sec for Drobo 5D)

  • Large Read: 220.192 MB/Sec (217.975 MB/Sec for Drobo 5D)

  • Large Write: 242.503 MB/Sec (219.885 MB/Sec for Drobo 5D)

  • Extended Read: 184.446 MB/Sec (198.243 MB/Sec for Drobo 5D)

  • Extended Write: 161.916 MB/Sec (228.985 MB/Sec for Drobo 5D)

These results are all much, much better than what we saw for the first-generation Drobo Pro under FireWire 800. For those tests, there were only two results -- write and read speeds -- and they weren't that good. Write speed was 29.3 MB/Sec, while read speed was 46.0 MB/Sec.

The Drobo Mini is much faster than the old Drobo Pro, especially when using a Thunderbolt connection. As you can see, most of the read and write speeds for both Thunderbolt and USB 3.0 are lower than they were for the Drobo 5D. However, the 5D tested had an mSATA drive installed for caching, while the Drobo Mini did not. If you need a really fast drive array, the Drobo 5D is probably more up your alley; if size is a constraint, consider the Mini but be sure to get an mSATA drive to install in the Accelerator Bay.


The Drobo Mini is a delightful compact update to the creative professional storage solution. It retains the ease of use and setup of the original Drobo products, but brings a surprising amount of speed to the game in a size that won't take over your desk.

Stay tuned for our final review of a new Drobo product -- the Drobo 5N NAS array -- in the next week or two.


  • Easy setup and configuration

  • Easily expandable storage; as drive capacities increase, drives can be replaced with higher capacity gear

  • Can be set up for single or double-disk redundancy

  • Drives are hot-swappable

  • Dual Thunderbolt ports for daisy-chaining

  • New, lower pricing

  • Has accelerator bay for adding cache via mSATA SSD


  • May not be fast enough for video professionals

  • Slight fan and drive noise (louder than the Drobo 5D)

Who is it for?

  • Anyone with a need for relatively fast, expandable, and reliable mass storage in a small physical footprint