We haven’t really talked a whole lot about the Qx2 on the OWC Blog, and that’s kind of a shame, because it’s a product I really, really like. In short, it is an easy-to-use, multi-drive storage solution.
External storage is insanely useful, especially for backups. In most cases, your standard single drive external storage solution will serve you well. However, while single-drive options are inexpensive, they are limited in speed and redundancy.
For FireWire and USB 2.0, most drives will be bottlenecked by the connection bus. With eSATA, though, the drive mechanism itself becomes the limiting factor, relying on how fast the drive itself can access the data. While OWC Storage Solutions use high-quality drive mechanisms, we have yet to find a single drive that can take up the entire SATA bus’s bandwidth.
The other place where single drives are limited is in data redundancy. When a drive eventually fails (which, granted, can be years from now), all the data on the drive is lost. Regular backups and/or clones are ways of getting around this, but they also are limited to only being as up-to-date as the last time they were run.
Both these limitations can be addressed by the use of a RAID device, such as the Qx2.
A little bit about RAID
For those of you who don’t know the term, RAID stands for “Redundant Array of Independent Disks.” Effectively, multiple hard drives are connected together and appear as one large volume on your desktop. There are a number of different RAID types, each with different levels of redundancy and speed.
RAID 0 (Striped) – This addresses the speed limitations of a single drive, and is a great choice for instances where fast data access is needed, such as video and audio capture. Data is split into blocks over two or more drives at same time for high speed and large capacity. However, if one drive goes down, the whole RAID array is ruined. Technically, you could say that this is not a “RAID,” as it eliminates the “Redundant” part. But that would be nit-picky, and nobody likes people like that.
RAID 1 (Mirrored) – This addresses redundancy issues, and is best for when you have data you can’t afford to lose to hardware failure. In this mode, data is written simultaneously to to two different drives. If one drive goes down, you still have a second copy. The down side to this is that you effectively lose half your total drive capacity.
RAID 10 (1+0) – This RAID level combines both RAID 0 and RAID 1, effectively layering one over the other. While you still maintain the speed of a RAID 0 and gain the redundancy of RAID 1, you still have the loss in capacity mentioned of RAID 1, only now you have TWO drives you lose the capacity of.
RAID 5 (Striped with Redundancy) – This is a slight variation on RAID 10, which addresses the capacity loss. In RAID 5, data is striped between 3 or more disks, with only one drive’s worth of data being lost to redundancy. In effect, the more Disks the RAID array has, the more space-efficient the RAID’s redundancy function becomes. For a more detailed description of how RAID 5 works, check out this informational PDF.
There are, of course, other RAID levels, such as RAID 6, RAID 0+1 & RAID 53, but they’re mostly just variants or combinations of these major ones.
The Mercury Elite-AL Pro Qx2 makes adding RAID functionality and massive capacity up to 8TB to your system incredibly simple. All you need to do is put four identical drives into the Qx2 case (or select one of the pre-configured complete solutions), and select the type of RAID you want (it comes pre-set as RAID 5…which is my personal preference incidently). After a few moments, the Qx2 will configure itself and you can then attach it to your computer via the connection of your choice, where it will behave just like any other external device.
I won’t kid you, the Qx2 isn’t for everybody. In fact, for many, a simpler solution may be more useful. For those in a “small office” situation or power users with more advanced storage needs, though, this may be just what you’re looking for.