Why You Should Never Buy Dual Drive (RAID 0) External Hard Drives

I came across this seemingly typical Engadget story today, announcing yet another 1 Terabyte external hard drive solution that utilizes dual hard drives, when I realized it was time to speak out out against these inane devices. These external hard drive setups have been marketed for the last couple years as a foolproof storage solution, but I would recommend them as the last place you’d want to store your precious digital wares.

The Trouble With RAID 0

The key to their troubling nature lies in their “ingenious” method for increasing disk capacity: Literally sandwiching hard drives together. External solutions such as these rely heavily on a geekilicious technology known as RAID (Redundant Array of Independent Disks). The technology is typically found in servers and desktops. It’s used to make several smaller hard disks appear as a single entity by “striping” the data across all the drives, something which also gives a boost to their overall performance. But it can also be used to insure the integrity of the data by automatically building a recovery structure within the array of discs.

This latter function, known as “Raid 1″, allows you to easily swap out a broken hard drive from an array of discs for a working one. Once a new hard drive is installed, the RAID array instantly repopulates all of the data that formerly resided on the old drive. This is what the paranoid geeks consider the good sort of RAID.

The former function of RAID (”Raid 0″) is less beloved among geeks. Performance enthusiasts like it for the speed boost, but overall those in the know would steer general users away from a RAID 0 array. This is because when they crash, they crash hard. Losing a single drive from a RAID 0 array makes it nearly impossible to recover any data because the data is shared across all the drives. Therefore, if you have a RAID 0 array with several drives and one happens to die–you can pretty much forget about the data on all the working drives as well.

Unfortunately, these external hard drives are of the RAID 0 variety. And not only that, these drives are often so closely sandwiched together in the external cases that they end up having a higher failure rate than normal due to the increased heat.

Recovering RAID 0 Data? Think Again!

As I mentioned above, it’s nearly impossible to recover data from any RAID 0 array — one used in an external hard drive is no different. I’ve written about recovering data from trashed hard drives in the past. It’s usually just a matter of finding a decent scanning tool (in my case “Handy Recovery 3.0“) and letting it seek through the remains of your hard drive to find any salvageable data. Sadly, the process is not so simple with RAID 0. If it dies, your only option is to send it to some sort of professional drive recovery outfit and be prepared to absorb the $1000+ repair fee.

And yes, you read that right. These recovery companies can often reclaim some of your data, but their prices vary depending on how much data is being recovered. Recovering much of a 1 terabyte era may very well cost you the same as a decent used car!

Avoiding Raid 0 External Hard Drives

Now that I’ve thoroughly struck the fear of the hard drive gods in you, let me leave you with some tips on avoiding these sorts of external hard drives in the future.

• If an external drive is 1TB or more, it is probably running RAID 0. At the time of this post, only one internal 1TB drive is publicly available. This means that the technology is very new, and most external hard drive manufacturers haven’t yet included this drive in an external case on its own.

  The above tip is not necessarily true any more since individual 1TB drives are actually common now.

• If the external drive weighs 5-6lb, it is probably running RAID 0. A typical external hard drive running a single hard drive is only about 2.5-3lbs. Logic would have it that anything twice that weight is probably that way for a reason ;)
• Research the drive. Most often you’ll find a review explaining the innards of the external drive.