While having the Mediasonic USB 3.0 RAID enclosure connected to my Mac Mini via FireWire 800, I did a very quick benchmark using XBench to get some results. Sequential Read and Write tests got acceptable results. Random Read and Write tests were affected by block size. I am sure if I can connect it using USB 3.0 or eSATA, I would be able to get slightly better results. From a practical sense, I was able to play 1080p MKV movies from this drive without any lag.
In terms of fault tolerance, I tested pulling 1 drive out while it was running. The RAID array continued to function which is what I expected. The Mac Mini didn’t report any problems because the enclosure hides the problem from the connecting computer. The “Hardware Problem” light on the enclosure lit up but the rest of the drives continue to deliver data. I was able to browse files on it, as well as playing a 1080p MKV movie with only 3 of the 4 drives active.
I formatted the drive that was pulled out, essentially destroyed the data inside. Then hot-plugged it back into the drive enclosure. The drive spanned up again and the “Rebuild” light on the enclosure lit up. It copied the data back to the drive while the array was still online. I was able to play a 1080p MKV movie from it while the RAID array rebuilt itself. That is pretty impressive. After using this enclosure for more than a couple of weeks, there are only a couple of minor issues I discovered:
- When connecting to the FireWire 800 port, only the port on the top can be used to connect to the computer. At first I was trying to connect the drive enclosure using the bottom FireWire 800 port but the drive would not start properly. It would try to start and then it would power down. After connecting it using the top FireWire 800 port, the enclosure was able to start properly. I think the bottom port is for daisy-chaining FireWire 800 devices. However, it is not documented anywhere in the documentation, nor is it marked on the enclosure.
- The enclosure itself does not have any power saving features. The only option is to control it via the operating system. I was able to put the drive to sleep by setting “Put hard disk(s) to sleep when possible” option in the Energy Saver system preference. However, when the drive is put to sleep, OS X reports the drive was disconnected unexpectedly. Maybe when OS X tries to put the drive to energy saving mode, it ends up turning the drive off.
Overall, I am pretty happy with the drive enclosure. It is painless to setup the RAID configuration and the fault tolerance features appear to be quite robust. If you need a fault-tolerant drive setup, this is definitely one of the cheaper self-managed drive enclosures that has relatively up-to-date connection options (eSATA and USB 3.0).