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What is a "Drobo"? Find out how to store massive amounts of data on spare HDDs.

16 Jul 2013  |  Tags: , , , , ,

Data backup is annoying. To be truly backed up, you need multiple copies of your data … in multiple locations, on multiple mediums. This way, if one place burns down, while a HDD (hard disk drive) has failed in another … you’re protected in the worst case. Hopefully.

I have seen so many people lose the single HDD in their computer, and it had all of their family photographs on it. They’re lucky to get any back from an expensive data recovery service. — Or, another horror story: a student loses all of their homework assignments that they were about to turn in when a computer slides off a dorm bed onto the floor. It is a nightmare come to life.

Luckily, nowadays there are services like Dropbox that offer a “backup in the cloud” … but Dropbox has its own issues with corruption or data loss. As previously mentioned, to be truly “backed up”, you cannot rely on a single medium.

Apple also has a great built-in service called Time Machine on Mac OS X that creates timely archives of your data whenever an external drive is connected. However, most people don’t set this up, it’s not expandable, and if that drive fails, you’ve lost your only backup!

What is a great, overall solution?

Hello, Drobo!

I bought a Drobo S. It has 5 drive bays, each with a 1TB disk in it. — I keep it stationary while I travel, containing an archive of adventures past. Music, video, photos, etc. — Old source code, things like that. Things I don’t need to carry around, but would like to retain access to.

I have alternate backups of this data, but Drobo provides a single, expandable, centralized volume that I can easily read from and search. If the Drobo fails, I still have another backup elsewhere. See beginning of article for the reason why.

My Drobo, setup and connected to an APC UPS for AC battery backup

(There’s a 5th drive bay and light on this Drobo, but it’s cut off by the top of this photo.)

Why Drobo?

There are other RAID solutions, but Drobo is the most user-friendly.

I needed something centralized and searchable, where I could put a second copy of data that was easily accessible. I have additional copies in other places, but this is great since it’s expandable.

The Drobo is not my primary backup of anything. It’s only a copy. The reason for this is that devices fail from time to time. You should never only have a single backup of your data! See beginning of article for why. :)

The Drobo is excellent for this and I like it. It’s so simple to maintain that I can even leave it at my parents’ house, and they can replace the drives if they fail … without my intervention. My father has actually done this twice for me, already, when the lights turn red on it.

Pulling scraps of data from random locations or random HDDs at various times is impractical. It’s easiest to have an expandable volume that can be maintained as datasets grow. Here comes Drobo.

Because the drives can be replaced at any time (without having to power the unit down) … you can just “hot swap" them. This can also increase the volume’s storage, too. Here’s a Vine video of me replacing a drive with a larger one to expand the volume:

Drobo devices are definitely very interesting, not to mention cool-looking!


The entire Drobo device could fail or corrupt, but so could your computer. Worse, since Drobo uses a proprietary filesystem … you’re pretty much screwed if it does fail since the drives cannot be accessed on their own.

The Drobo S has two features that I really liked that made me more comfortable, though. One was Dual-Disk Redundancy … meaning that if you have a drive completely fail, and then the unit discovers that another drive is also dead, you’re only screwed if a THIRD drive fails. That is great. Also, unlikely.

The other feature that I liked was that it constantly scans/scrubs the drives for errors. This leads to faster drive “failures” than most other RAID systems, but also guarantees that the device is not relying on a failing/faulty piece of hardware. Ordinary RAID systems generally have catastrophic failures because they do NOT do this, and therefore when a single drive begins to fail and the RAID becomes degraded, it notices its other failing drives as it begins to recover from the other parts of the array. Scary!

In addition to all of this, there’s also the fact that the Drobo has lights in the front of the device to alert the user to when a drive should be replaced with a larger one, or if a drive has failed. So, unless you hide the Drobo in a closet and don’t look at it, chances are you will notice a problem and fix it before it is too late! That is, unless the entire unit fails….

One serious design flaw in Drobo: When you setup your Drobo, you choose the “size” of your Drobo volume. In other words, when you connect the Drobo to your computer, even if you only have a single 1TB drive in it … your drive will appear as “4TB” if you chose a “4TB” volume size. The sizes vary, but I believe the maximum is 16TB:

Drobo "Volume Size" chooser

This only becomes a problem if you put too much data on your Drobo. The “Drobo Dashboard” software can alert you to your Drobo becoming too full, but if you continue to fill it (or an automated copying/backup utility does this for you since it thinks the volume is large enough) … it can become corrupted and the data will be irrecoverable.

Putting too much data on, as other users have reported, destroys the Drobo volume. I cannot confirm since I always try to leave at least 25% free, but damn!

Why do they make it configurable in this way, you might ask? It’s to make the unit upgradable. You can start with 2TB of physical space (which Drobo may allow you to use just over 1TB of) and add two more 1TB drives later, for a total of 4TB then. You could even swap one of the 1TB drives out for a 2TB drive after that, and so on. This design is for expansion and versatility, but you need to police it slightly. This design is one of the consequences of being able to mix-and-match drive sizes and brands in a dynamic, expandable storage array. Normally, traditional RAID arrays simply max out and must use identical drives for a fixed volume size.

Also keep in mind that peoples’ Drobo units fail all of the time, apparently. Just search the web, you’ll find tons of stories. Also, irrelevant to Drobo, peoples’ hard drives fail all of the time. — So, please… always have a “backup of your backup” … and absolutely NEVER keep data only at a single location on a single device/array.

What drives to buy

When buying hard drives, go for the best quality!  And, buy each drive from a different retailer, at a different time!


Perhaps a shipment of drives was mishandled and subjected to high shock. Perhaps a batch of drives from the manufacturer were faulty.

These are situations that you do not want to have to worry about. Rather than setup your entire RAID array or Drobo in a weekend … order the drives over the course of a month or two. Check the manufacture dates and be sure that they are all different. This way, you should be safe. Paranoid, but safe.

In terms of recommended manufacturers and models, Drobo actually recommends some models here: http://www.drobo.com/products/choose-drive.php

In general, the more expensive the drive, the better. However, some are overkill and higher performance than what you need.

I opt for enterprise level drives. These are often slightly louder when operating, but have a solid warranty and are reliable. — My personal favorite is the “Western Digital RE4 1 TB Enterprise Hard Drive: 3.5 Inch, 7200 RPM, SATA II, 64 MB Cache" … as, the "RE4" line is recommended by Drobo, as well. — These cost about $100 USD each.

I used to use “RE3” drives (the previous generation) when building RAID Arrays, and have had good luck with them. I trust the “RE4” drives, but you should still order each drive from a different retailer at a different time to be on the safe side!

If an “RE3” or “RE4” drive fails in your Drobo, Western Digital has a support portal through which you can request a replacement drive during the warranty period. The warranty period at this time of writing is 5 years! All drives will fail eventually, but that is a massive window in which you’d receive a complimentary replacement.


A properly configured and ventilated Drobo that is taken care of, I imagine, will be a very reliable device. I have not had any catastrophic failures with the Drobo S that I use, but it is also one of their older 2nd generation products and has had ample time for debugging. Your results may vary, but I wouldn’t be writing about the Drobo if I wasn’t enjoying its performance thus far.

Keep in mind that from time-to-time, Drobo does issue firmware updates. These can correct issues and increase reliability. As mentioned, I haven’t had any failures yet. But, to be sure, always have a second and third copy of your data elsewhere.

In terms of an expandable, redundant storage array, there is nothing else quite as friendly as Drobo. I’m excited to see what their future products look like as data storage evolves, and to keep maintaining my Drobo by swapping out drives when they fail so that my data stays intact.

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