The Drobo is a mass storage solution that takes advantage of RAID -- Redundant Array of Independent Disks -- to provide a single large volume by combining two to four "naked" (not in an separate enclosure) hard disk drives. Drobo uses a proprietary system called "BeyondRAID" to do this while eliminating a lot of the administrative headaches that are normally associated with setting up RAID arrays.
Drobo uses a combination of RAID 1 (mirroring) and RAID 5 (striping) to provide relatively fast response times and redundancy. If a drive fails, you simply pop it out of the array and pop in a new one. Drobo takes care of rebuilding the new disk while the array is in use. While many traditional RAID solutions require all drives to have exactly the same capacity, you can mix or match drive sizes with Drobo. This makes storage growth quite easy to manage -- as new, larger capacity hard drives appear in the future, you just need to pull out a smaller drive or two and replace them with the larger drives. Drobo takes care of integrating the new disk or disks into the array. Click the Read More link for the rest of this post.
While I had read about Drobo for the last year or so, I didn't have an opportunity to try one until now. One of my consulting clients was moving from an undersized Mac mini server to an Xserve, and I needed to provide them with a large amount of storage due to rapid expansion of their business. Doing my duty as an Apple Consultants Network member, I promptly worked up an estimate for an Xserve with the standard Promise V-Trak E-Class Fiber Channel RAID subsystem. The storage alone for this solution costs about US$7,499, and the client balked at the price tag.
I knew that the client needs up to 4 TB of storage in order to meet growth over the next three years. Their needs aren't for fast storage (i.e., they're not doing any video work), but they just need a big ol' empty bucket to store their files in. That's when I started thinking about Drobo.
Using the "Drobolator" application on the Drobo Web site, I dragged four virtual 1.5 TB SATA drives to an image of a Drobo. What I found is that using four 1.5 TB drives would provide just over 4 TB of actual storage (the other space is needed for protection and overhead). The total cost of this solution was fairly reasonable as well. The 2nd Generation Drobo with FireWire 800 and USB 2.0 sells for US$499 empty, and I was able to find 1.5 TB SATA2 7200 RPM bare drives for $129 each. The total cost of the solution? Just over US$1,000 plus tax and shipping. Needless to say, the client approved the estimate.
Someone at Drobo must have taken a cue from Apple in their design and packaging, because both have a very "Mac-like" feel. The product is incredibly easy to set up and use. After pulling the Drobo out of the box and removing the requisite plastic protective film, I popped the front cover off of the device, and then pushed the four 1.5 TB drives into their respective cubby holes (see photo below). The mechanism for doing this is very easy to use, and removing the drives is a simple matter of just moving the small lever gray lever on the left side of the drive and pulling the drive out.
The next step was installing the Drobo Dashboard software on the Xserve. Drobo Dashboard can be used to monitor the drives, even sending email alerts when a drive is about to fail or the array is running out of space. Once Drobo Dashboard had been installed, I was prompted to plug in the Drobo and attach the Firewire 800 cable between the Xserve and the Drobo (see photo below to see the how the plugs are arranged on the device). After a few seconds, the Drobo appeared on the Xserve desktop, completely ready to use. I formatted the array as Mac OS Extended (Journaled) and I was on my way. The format took no time at all to complete.
I moved about a terabyte of data from the client's old drives to Drobo; the transfers were surprisingly fast over Firewire 800, although I had the occasional delay as Mac OS X Server refused to copy some files. Since I hadn't yet made the server available to my clients, I did some testing by opening up a 2.1 GB movie file on the Drobo, then yanking one of the drives. Just like Drobo advertises in the Cali Lewis video on their site, the playback continued without a hiccup.
Once the front cover is back on the front of the Drobo, all you see are some lights. Green lights next to installed drives indicate that the drives are working as they should. Yellow indicates that the array is about 85% filled, and you need to either add a drive or replace an existing drive with a larger capacity one. Red means the Drobo is at about 95% of capacity, so you'd better get that new drive now! Blinking red is even more of a worry, as it's telling you that a hard drive has failed. The blue lights along the bottom each show that 10% of the total storage space has been filled up with your data. All of this information is provided on the inside of the front cover, just in case you forget (see photo below).
RAID purists always seem to sneer at the Drobo as not being "true RAID", but since installing the device I've realized that it really brings RAID to the masses. I know that I could call one of my non-technical clients when the Drobo sends me an email saying that a drive is about to fail, tell them to get a spare drive from a box, pull out the old drive, and put the spare into the Drobo. That's all they'd have to do in order to start rebuilding the array.
Since 2 TB disk drives are starting to appear, the Drobolator tool has been updated and you can now simulate Drobo capacities with the 2 TB drives installed. With overhead and protection, the maximum capacity of a Drobo is now up to 5.5 TB when four 2 TB drives are installed. That maximum capacity will continue to grow to the theoretical maximum of 16 TB per Drobo as drive capacities increase.
Have I seen any issues with the Drobo? Not really. I did have some concerns over the fact that the device can't be used to perform over-the-network Time Machine backups when connected to a Mac or Xserve. You can do Time Machine backups for the machine that the Drobo is attached to, but not for Macs connected over the network. Data Robotics has a Linux-based NAS solution for Drobo called DroboShare (US$199) that can connect up to two Drobos to gigabit Ethernet. There are DroboApps available for DroboShare that allow it to back up remote Macs using Time Machine, so that's always a solution in case backing up all of those Macs in the office is required.
The Drobo is extremely small -- 6.3" x 6.3" x 10.7" (152.4 mm x 160 mm x 271.8 mm) -- and very quiet. I'd gladly trade my existing 1 TB drive with its noise for one of these. It's also fairly energy efficient, using only 40 watts when operating at full capacity with four drives installed. If I have any complaint about the design of the Drobo, it's that the case seems to be a dust magnet (see photo below). Of course, there was construction still going on in the office when I was installing the equipment.
There are some alternatives to Drobo; HP's MediaSmart Server EX485 (US$599 with 750 GB drive) works very well with Macs and has a similar price tag to the Drobo. However, it requires all four bays to be filled with the same size and speed of hard drive.(Update: HP contacted us and let us know that the hard drives can be of different sizes, and not all four bays need to be filled with drives. We will hopefully be doing a review of the MediaSmart Server EX485 in the near future) LaCie has the 4big Quadra (US$799 for 2 TB) that also requires identical drives.
I've personally enjoyed working with the Drobo and have decided that I personally need one for my backup and storage needs. If you're a Drobo owner or use a different solution for mass storage, I'd love to hear your feedback in the comments section.