Review: OWC’s RAID Box, Looks like a Mac Pro (runs like one too)

The Mercury Elite-AL Pro Qx2 4 TB RAID Enclosure from Other World Computing

Last month, we discussed the very popular and oh-so-easy data backup machine, the Drobo from Data Robotics (reviewed here).  This month, I’m happy to be featuring a robust product from a favorite vendor, Other World Computing.  The company is deeply nerdy and uniquely dedicated to Mac computing peripherals and supercharging, under-the-hood toys like the 12 GB of RAM in my studio Mac Pro.  Without any promise of financial gain, I would be quick to proclaim that OWC is the place to go to turn your Mac computer into a data-blasting professional Work Station.

So this little box?  Well it’s no coincidence that it Looks like a cute, miniaturized Mac Pro.  OWC has established themselves as a one-stop shop for everything Mac hardware.  The box is an automated RAID box, meaning that it accepts four hard drives (four Hitachi 1 TB units in our demo unit) and, with the twist of a dial, will go to work configuring its drives in RAID 0, RAID 1, RAID 10, RAID 5, or a non-RAID spanning set up.  It spares the Mac owner of the time, hassle, and uncertainty of performing such maneuvers in Disk Utility, and, indeed, once things are set up, you’ll see one big, beautiful drive ready for Time Machine, Chronosync (reviewed here), Photoshop scratching, or Lightroom importing, with very little effort.

So how does it work?  Read on for a full review…


It is a pretty box, every bit as robust as the big tower it emulates.  Compared to the Mac Pro, the Mercury Elite-Pro Qx2‘s surface is not identical, but more textured and sparkly.  It is metal, and substantially thick metal at that.  It is heavy, has wonderful silicone feet, and feels like a tank.  The metal front panel has a large grill for cooling air from the rear fan to exit, a row of labeled LED lights and a key for access to the box’s guts, which include more LEDs, drive access, and the RAID mode selector.  Using the key, the front panel is removed for drive maintenance.  It isn’t as slick a process as the Mac Pro’s hood-removal lever, but it is space efficient and functional.

The metal rear panel (all metal, this box) is dominated by a cooling fan.  It includes an on-off rocker, power input, locking cable connection, and data ports.  All the right players are present: USB 2.0, firewire 400, eSATA, and two firewire 800 plugs.  For my testing, I used the unit’s eSATA port, which works very well.  If they haven’t already, serious data movers will certainly want to consider adding an eSATA card to their Mac Pros, and, as it turns out, OWC can hook you up with one.

Inside the box are four vertical hard drive bays.  Drives attach with up to six screws to metal brackets that slide firmly into place and are held with one large thumb screw.  The insertion is reassuringly snug and sturdy.

The unit arrived to us well packed and with all the right connections including, firewire 800, firewire 400, USB, and eSATA.  The drives, packed separately and securely, are labeled by bay (A, B, C, and D).  I was impressed to see that, once assembled, powered up, and running, the drive appeared on the desktop of our OS-X 10.6 (Snow Leopard) Mac with a custom icon and 3.0 TB of available space.  As configured on arrival, the box is set and pre-formatted as a RAID 5 array (Mac OS Extended, Journaled) and loaded with an interesting set of shareware of demo software.  Formatting, including zeroing out data in OS-X’s disk utility, took about 4 hours on our machine for the pre-built RAID 5 array running on an eSATA connection.

Turbo Charging with RAID 0 – RAID 5 is likely the box’s most oft-used array setting, offering a nice balance between speed, available space, and redundancy.  To get the OWC moving at turbo speed, though, I reformatted it as a bare bones RAID 0 array.  An excerpt from the user manual says:

“[Disk Striping is] used when speed is the primary objective but RAID Level 0 (also called “striping”) is not redundant. This array splits each piece of data across the drives in segments. Since data is written without parity data-checking, it allows for the fastest data transfer rates, but if one drive fails, the whole array can become corrupted”

The process of dangerously boosting the drive, though exciting, is very easy.  I “ejected” the drive from the desktop, turned it off, rotated the RAID mode dial to “4” and fired it back up.  Within a few minutes, the array was rearranged.  From OS-X’s Disk Utility, I reformatted the drive, zeroing data, to create a high speed, 4 TB, bullet drive.  The reformatting took a few hours and created a large, zippy drive ready for heavy use, like Photoshop scratching, or file organization.  4 TB makes for a large drive, RAID 0 makes for a quick one.  The arrangement is a good set up for a working volume, provided the whole rig is backed up with a second RAID.

Test Notes: Using the shareware drive speed tester, Xbench, I was impressed to see the RAID 0 array match or outperform the performance my Mac Pro’s internal drives in read and write speed, most notably in the area of Sequential Uncached Writing of both 4k blocks and 256k blocks.  There are many factors contributing to drive speed, and the OWC had a huge advantage, being new and just formatted, but it’s safe to say the big box on RAID 0 is quick!

Drive Cooling – Very important for hard drive longevity is good cooling and the Mercury Elite is well prepared to radiate.  The spacing of the drives, inline with the large fan and open front grill provide good active cooling while the thoroughly conductive components help to draw heat away from the plates and out into your studio.  When compared to the Mac Pro tower (which, like all Apple products, runs notoriously warm) drives nestled in the OWC box get a steady stream of cooling air all to themselves.  Drives in the Mac tower are lined up, shoulder to shoulder, with a stream of air moving below.  In the OWC, it moves around them for double the surface area in contact with cool air.

The cooling of OWC’s Mercury Elite Pro-AL is good, a definite step up from the Mac Pro.  It’ll keep hard working drives going for years.  There are units on the market with even more air-moving power.  My studio has been running a Mac Guru’s 4-bay RAID box for two years that has five fans, including one per drive.  It really keeps down the heat and would be a quick recommendation to keep hard working drives cool.  On the other hand, the OWC box is a fraction of the size and significantly quieter.

The Audio Experience – I appreciate that the Mercury Elite Pro-AL varies fan speed by thermostat and is very quiet when full throttle is not needed.  At full throttle, which we only heard on startup, the unit is louder than our Mac Pro tower, but reasonable.  The box also has unusually prominent audio feedback.  The box comes online with an authoritative beep and, when turned off, emits a sound like a sonar ping on a submarine.  When drive failure was simulated with a physical disk removal, a red light indicated the failing drive and a repeating double beep drew attention to the issue (the alarm can be silenced with the unit’s mute button).  With the drive pushed back in, the unit quickly recovered


RAID Options

The Mercury Elite Pro-AL Qx2 has a RAID mode selector switch with nine settings.  As described in the Use Guide, the options are as follows:

Switch Position ~ Function:

0 ~ Not used

1 ~ SPAN, Spanning with two hard drives

2 ~ SPAN, Spanning with four hard drives

3 ~ RAID 0, RAID 0 Striping with 2 hard drives

4 ~ RAID 0, RAID 0 Striping with 4 hard drives

5 ~ RAID 1, RAID 1 Mirroring with 2 hard drives

6 ~ RAID 10, Mirroring and Striping with 4 hard drives

7 ~ RAID 5, RAID 5 with three hard drives

8 (factory setting) ~ RAID 5, RAID 5 with 4 hard drives

9 ~ RAID 5, RAID 5 with 3 hard drives and one spare

The manual devotes a quick paragraph and ratings for storage capacity, data safety, and performance to each setting and is a useful reference when setting up the box.  Essentially, users install between two and four hard drives, choose a setting, and fire up the box.  Once it’s ready, plug it in, format, and you’re ready to go.  It’s a very easy approach to RAID, allowing clean partitioning using OS-X’s Disk Utility.

Selling Points

The OWC Mercury Elite Pro-AL Qx2 is very well made, very sturdy, and built to last.  It nicely mimics the aesthetics of high end Mac computers and will keeps four hard drives secure.  It offers ample cooling and secure mounting for drives.  The box has a wide range of RAID options and makes setting them up very easy.  Depending on drives, the unit currently tops out at 12 TB capacity.  When set to RAID 5, the OWC default, the box allows for automatic recovery from the failure of a drive (just swap in a new one and give the little box time to rebuild).

As best practice, I’d recommend having the whole assembly backed up.  In my studio, I have one RAID array backup up to a second, in addition to the multiple drives in my Mac tower.  Automatically, using Chronosync (reviewed here), the working disks in my computer are backup up every night to the first RAID and that’s backed up once a month to the second RAID.


Other units, like our studio’s Mac Guru Burly Box offer even more cooling, but depend on OS-X’s Disk Utility to set up RAID options.  Instead of a Mac Guru’s style port multiplier which allows the computer to interact with each drive, the OWC box interacts with the computer as one big drive (which can then be partitioned).  Port mulipliers are more complicated to operate, but they are not without advantages.  A 4-bay box with port multiplication, for example, can be set up, in Disk Utility, as two RAID arrays of two disks each.  One can be a back up of the other.  The OWC box allows for two pairs of RAID 0, but they are automatically mirrored, meaning accidental deletions or alterations will be carried out on both arrays, which defeats one major purpose for having a backup copy in the first place.

Also, when it comes to four-bay RAID enclosures, it’s a crowded market.  Notable competition is amply provided by Netgear, Western Digital, LaCie, and many more.  It’s important to note, though, that not all boxes automatically splice disks into a single RAID array, nor do many offer so wide a range of options for how it’s done.  Also, there are even easier units available like the popular, though significantly less rugged Drobo (reviewed here).  The Drobo removes all worry over RAID settings by using a mysterious proprietary version that is uniquely competent with mismatched drives, redundancy, and rebuilds.  When compared to the Drobo, the OWC adds more control, more cooling, and beefy metal build.


The OWC Mercury Elite Pro-AL Qx2 is a rugged and easy-to-use four-bay RAID enclosure that automates RAID set up and allows an impressive 8 options for how disks are put to use.  The unit’s build quality is top-notch and it is a nice quality and aesthetic match to the Mac Pro tower it closely emulates.  It is available in several capacities, including a relatively new option to be ordered without drives.

Certain traits concede that it isn’t actually designed by Apple, like a Star Trek rainbow of winking LEDs, and a low-tech, though functional front door.  Where it really counts, the box is hard to beat.  it offers good active and passive drive cooling (fan is thermostatically controlled for quiet operation) a nice set of data connection options including both eSATA and firewire 800, and unmistakable audio and visual feedback in the event of a drive or fan failure.

I have no hesitations in recommending the Mercury Elite Pro-AL Qx2 as a great fit in any studio’s DAM plan.

Image Slideshow
Join the Discussion

To comment on RAID, the OWC, DAM, and other Photo Arts Monthly articles, join us on Facebook.  Also, we appreciate the financial support we get when you use the sponsor links at the bottom of this page and links throughout the site for your shopping.  Please use the below buttons to share this article far and wide; thank you!

by Matt Beardsley – all photography by Matt Beardsley

Comments are closed.