The Drobo Mini is like no other Thunderbolt storage device I've reviewed before. For one, it's very compact, yet its four drive bays mean it can host up to four 2.5-inch hard drives. Secondly, it's the first multiple-bay Thunderbolt storage device that also supports USB 3.0, and the first Thunderbolt device I've seen that offers a ceiling storage space of up to 16TB, despite having just 4TB of actual raw storage at most, thanks to Drobo's flexible BeyondRAID setup.
And finally, it's got a slew of unique little features including an mSATA drive bay, a built-in emergency battery, a cool magnetic drive bay door, and many colorful LED status lights. There's also a little bit of money-saving: like most recent Thunderbolt storage devices, the Drobo Mini comes with the necessary Thunderbolt cable included.
On the down side, at the time of the review, the Drobo Mini bears a crazy price tag of $650 with no storage included; it takes a long time to start up; and it's noisier than most Thunderbolt devices I've worked with. In terms of performance, when hosting four high-speed 2.5-inch hard drives, the drive fell short in my testing when compared with its peers, using both Thunderbolt and USB 3.0 connection types.
That said, if you don't mind spending money on uniqueness, the Drobo is available now, though you won't find it at Apple's store, where you'll find most other Thunderbolt storage products. For productivity, remember to also check out the alternatives on this list. For example, for just $500 the WD My Book Thunderbolt Duo offers slightly faster overall speeds, 6TB (or 3TB protected) of storage space, and a much more straightforward experience.
Measuring 7.3x1.8x7.1 inches, and weighing just about 3 pounds (with the four drive bays fully loaded), the Drobo Mini is the most compact four-bay storage device I've seen. This is mostly because it's designed to house 2.5-inch laptop hard drives and not the regular 3.5-inch desktop hard drives. The Drobo Mini is not exactly "the size of a deli sandwich" as described on Drobo's Web site, however; rather, it's about the size of a Mac Mini, slightly thicker and heavier, in fact.
On the front, the Drobo Mini's drive bays are covered by a magnetic lid that stays on easily and firmly. It's a little hard to remove this lid, however, mostly because it's very smooth and kind of slippery, and there's no handle to grab. You just have to jiggle it around and eventually it'll come off, revealing the four drive bays. Each of the bays can host a 2.5-inch standard high-speed drive, be it a hard drive or solid-state drive (SSD). Since standard high-speed 2.5-inch drives on the market are currently capped at 1TB, the Drobo Mini offers up to 4TB total of raw storage space, or 3TB of usable capacity with data protection. The drive bay can house a drive that's either 9mm thick (standard) or 7mm thick (ultrathin).
It's very easy to insert a drive or remove it from its bay; no tool is necessary, since each drive can be pushed in its place. To remove it, you just push again and it will come out. This is very similar to how you use an SD card with most digital cameras, which is as well-designed as can be.
Wrapping around each of the drive bays is a bright LED light that stay green when everything is in order. When something happens, such as a drive has crashed (or was pulled out during an operation), the color of the light will change to red. During a RAID rebuild, all of the lights of the four drive bays will be flashing green and amber. This is a helpful feature when something is not right. Most of the time, however, I find these lights too bright and they can be an annoyance when you want to keep the room dark. Especially considering that the Drobo Mini has even more lights.
It's true: also on the front, at the bottom edge, the storage device has three more LED lights, two little ones that show the power status (always green) and activity (flashing green), and a long blue light that works as a storage gauge: from left, it partially glows brighter to indicate how much of the total capacity has been used up. As you can imagine, all these lights make the front of the Drobo quite busy to look at, especially while the drive is starting up, when these lights are constantly flashing or changing colors or both. The good news is you can use the Drobo Dashboard software to dim these lights.
And the Drobo Mini takes a long time to start up, ranging from 1.5 minutes to a whole 4 minutes in my trials. Other Thunderbolt storage devices take just a few seconds to be ready. This in itself could make the drive a terrible choice as an external storage device when you are in a hurry.
On the back, the Drobo Mini has two ventilation fans on both of its sides. These fans run all the time starting from the moment you turn the drive on, and they're noisy. In fact, the Drobo Mini is the noisiest compact storage device I've used, rivaling even the Pegasus R6, which is a huge device, about six times the physical size of the Drobo Mini. Again, together with the excessive number of LED lights on its front, the Drobo Mini's noise could really be a nuisance for many users.
Also on the back, the drive has two Thunderbolt ports (which is standard for most Thunderbolt storage devices), a USB 3.0 port, a power port, and a power on/off button. It's important that you use this power button to turn the drive off. This is because if you unplug the drive from the power source, it won't turn off right away. The Drobo comes with a built-in battery that keeps it alive when the power goes out spontaneously, "for the data to be written to nonvolatile storage," according to Drobo. While this seems like a good data protection feature, in my trials it was, again, more of a nuisance.
When I unplugged the power to the drive to simulate a power blackout, the device would stay on though its fans turned off immediately, but it was also immediately dismounted from the computer, as though its Thunderbolt cable were unplugged. To be clear, if you are working on a file or copying data to the drive and the power goes out, the data will still be lost. Now when I plugged the power back in, the drive would turn back on with fans back on loudly, but would not be recognized by the computer for a few minutes; then it appeared to restart by itself, so would be another few minutes before it was back to normal. From the users' point of view, the built-in battery is quite useless and seems to only make life harder.
In addition to the four drive bays on the front, the Drobo also has an mSATA SSD drive bay on the bottom where you can install an mSATA SSD. Drobo calls this bay the Accelerator Bay, claiming that it will boost the performance of the Mini when an mSATA SSD is used. Whether this performance boost happens is to be determined -- I didn't try that out -- but for sure this will increase the total cost. On a good day, a 64GB mSATA SSD can be as cheap as $70, but larger drives will cost significantly more.
Setup and features
Generally, there's basically nothing to the setup process of a Thunderbolt storage device. For most of them, you just have to plug the drive into a power outlet and the computer, using a Thunderbolt cable, and that's it. Within a few seconds you can use the drive. With others, you might have to format the drive using the Disk Utility (Mac) or Disk Management (Windows), a process that takes less than a minute to do.
It's quite different with the Drobo Mini.
Out of the box, the Drobo Mini comes with no storage, but Drobo shipped the review unit with four 750GB Seagate Momentus 2.5-inch hard drives for me to use in testing. These are high-speed laptop drives that spin at 7,200rpm. It was easy to install these drive in the Mini's four drive bays, as mentioned above. The Mini also comes with a standard USB 3.0 cable and a foot-long Thunderbolt cable.
Using the drive as an external storage drive, however, required many more steps. First I had to download the Drobo Dashboard software from Drobo's Web site. During the installation of the software, it suggested that I cancel the process and install Java first, which I did. After that, I reinstalled the software from the beginning, and had to restart the computer to complete the installation.
The software took about 30 seconds to recognize the fully started-up, plugged-in Drobo Mini and took about 5 minutes to format it into HFS+. Now there was something interesting about this process. The Dashboard software, by default, suggested that I should pick 16TB as the total storage space of the Drobo Mini, while in fact with the four hard drives, it has at most 3TB of raw storage space. As it turn out, with Drobo's BeyondRAID, you can choose ceiling storage space of anywhere between 1TB and 16TB, regardless of the actual capacity of the Mini. As you use the drive, and the actual storage space runs out, you can then add more storage either via more drives (if you started with fewer than four drives) or via drives of larger capacities, up to the amount determined by the ceiling volume. Given that, there seems to be no benefit to picking less than 16TB as the initial volume size.
But there's no benefit to picking the highest amount, either, since each of the Mini's four drive bays supports a drive of 1TB at most. For that reason, it's kind of pointless to select a volume that's larger than 4TB. Having a "virtual" volume that's larger than the actual storage space can also be confusing since you end up thinking you have more storage that you actually do. Our review unit, with four 750GB hard drives, actually offers about 2TB of protected storage space with one-disk redundancy, or 1.3TB with dual-disk redundancy.