Marti's blog

If you have any large quantity of data to handle, you know the problem: backups! Sure, it's easy to get a bunch of large external hard-drives, but hard-drives are mechanical devices that can (and sadly, do) fail once in a while. There are many solutions around this problem, the most common being to have twice more drives and do copies. It's long and painful, but not as much as backuping a Terabyte of data with a pile of 4,7 Gb blank DVD-RW (ouch!).

Now if you can live with the idea of not having "real" backups (as in, a perfect duplicate of your data stored in a separate place), but want to protect yourself from drive failures, there's the option of RAID hard-disk enclosures, which use multiple disks to provide redundancy:

• RAID 1 does mirroring: half of the hard drives mirror the other half. It's simple but you give up 50% your total capacity to security.
• RAID 5 uses a parity system: the equivalent one drives is lost to parity, while 1 to 4 other drives can hold data. It's much better as you loose between 20 to 50% of your total capacity.

From there a RAID 5 box seems as the best option, but there's a catch: it's complicated to set up and tricky to maintain. You must fit it with 2 to 5 strictly identical hard-drives, which means that if you want to upgrade to newer drives, you have to discard all of them, buy a bunch of newer ones and store your data somewhere else during the swap.

This brings me to the subject of this post, Drobo. Data Robotics brands it as «the first robotic storage», which is probably a bit excessive for what is basically a smart RAID enclosure. It's still a promising product nonetheless: plug the Drobo into a USB 2.0 port (more on that later) and add 1 to 4 hard drives to it, it just works. The drives don't have to be the same hard drives. You don't have to configure anything. Just add hard-disks as your storage needs increase and Drobo will take care of handling redundancy. If a drives fails, or if you need to upgrade some to larger capacities, just pull that drive out and slide in a new one – you can do that even as you are accessing files on the Drobo and it will keep going on seamlessly.

How much disk space do you loose to redundancy? Apparently Drobo uses a mix-n-match of mirroring and parity depending on the space and drives available, but its maximum capacity is the total of your hard-drives minus the larger one, which is as good as RAID 5.

Now for the downsides: connectivity is USB 2.0, which is not very fast and doesn't have the sharing practicality of a network plug. It also means you cannot have more than 2 Terabyte per volume, so if you fill it up beyond this capacity you'll have to work with two or more volumes. It's not cheap either at $499. Lastly, it's only sold in the US, so poor Europeans like me have to wait and hope. Which is pretty sad because, well, I really want one.