I previously mentioned the Highpoint RocketStor 5212 (Amazon), which is a dock for dual 2.5- or 3.5-inch hard drives that connects via Thunderbolt. USB 3 has always seemed plenty fast to me for backups, so I initially dismissed the RocketStor and its high price. However, I continued to have problems with hard drives spontaneously unmounting during backups. This would, at the least, interrupt hours of work, and at the worst corrupt the data. In some cases, the only way to complete a backup was with multiple passes of SuperDuper’s Smart Update, each one copying a different set of files before failing, until finally all were copied.
The problems occurred with both the NewerTech Voyager S3 (Amazon) and the Anker USB 3.0 Hard Drive Docking Station (Amazon). It occurred with multiple Macs, multiple (of each) drive docks, multiple hard drives of different capacities and brands, multiple backup apps, multiple uninterruptible power supplies (as well as none), with and without any other connected USB devices (including hubs), and in multiple buildings.
I reported the problem to the manufacturers, who seemed not be aware of it, and received replacement drive docks, which didn’t work any better. I also got some recommendations for other brands, although the Amazon reviews did not inspire confidence.
I still don’t know what’s causing these problems, nor why they only affect some users. However, my hypothesis is that it’s related to USB 3. There may be a bug in the Mac OS X driver, although I’ve seen similar reports from Windows 7 users. Perhaps the bug is with the USB 3 on the docks themselves. In any event, every USB 3 drive dock I’ve tried has had the unmounting problem, and none of my older USB 2 drive docks did. (Unfortunately, USB 2 drive docks are much slower and only support capacities up to 2 TB.)
The obvious solution was to try a drive dock that doesn’t use USB 3. This brought me back to the RocketStor, whose price has come down from $219 to $190. Result: through many hours of backups as well as regular use, the RocketStor has never spontaneously unmounted a drive.
The RocketStor has some other good points:
- It seems to be faster than the USB 3 docks, even though my 3.5-inch drives are not high-performance models and they are encrypted with FileVault 2.
- The power plug isn’t a brick.
- As a dual dock, it has fewer cables and takes up less desk space.
I also found some problems:
- Despite the much higher price—the Voyager S3 is only $37—the RocketStor does not come with a Thunderbolt cable.
- There is only one Thunderbolt port (no passthrough). My MacBook Pro only has two ports, so with an external display and the RocketStor, I can’t connect any more devices. Any additional external storage must connect via USB.
- On the front of the dock is a bright blue light that’s always on, even if no drives are inserted.
- Drives do not always spin down when unmounted.
- There is no power switch, so after unmounting a drive you have to remove it from the dock (or unplug the dock) to actually turn it off.
- Each drive has an eject button, but it almost never works. That is, I can push the button all the way down, and for most types of drives this does not actually move it enough to disconnect it. The drive is still spinning. I reported this issue to Highpoint. They were unfamiliar with the problem and offered a free exchange—I paid return shipping while they cross-shipped—but the replacement RocketStor had the same problem. I’ve taken to pushing the drive’s top corner to the side in order to disconnect it. Then I let it sit, at an angle, for a while so that it fully spins down before I remove it from the dock.
- After booting the Mac, the initial drive insertions work correctly, but sometimes after ejecting one drive and inserting another, the new drive spins up but doesn’t mount. This problem occurred on both my RocketStor and the replacement. The workaround is to unplug and replug the Thunderbolt cable—make sure you’ve first unmounted the drive in the other slot—or to restart the Mac. With recent versions of Mac OS X (now running 10.9.3), this problem occurs less frequently.
All of this is to say that I consider the RocketStor a flawed product, but I’m grateful to have it because once a drive is mounted it stays mounted. Sadly that seems to be a lot to ask of a storage product these days.
Update (2015-05-08): The price at Amazon is now down to $147.
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