Instruction: Answer the given question using the supporting document.

Input:
Question: Is the RAID processing done on board within the ProRAID, or is it done via an interface card on the computer?
Document: The Mediasonic is connected via eSATA using a NewerTech MAXPower eSATA 6G PCIe 2.0 Controller Card and a 6' StarTech Shielded External eSATA Cable. I have the enclosure set to 2x Raid 0 (striping) with four 2TB drives in the top controller (partitioned using Disk Utility to two 4TB volumes) and three 1TB drives in the bottom.
Does not provide the speed you'd expect from a RAID. With 4x SATAIII drives in a raid 0, connected via usb 3.0, it only gives about 75 to 80MB/s, no faster than a single drive. In RAID5, it only maintained a transfer speed of 35MB/s. For $100 more, you could get a good internal hardware raid controller.
This unit is working great on my OS X 10.6.8 system connected via USB 2.0. I have it filled with 8 3TB drives configured as 2 independent RAID 5 arrays. Though I've only had it a few days so fat I do like it a lot.I really feel like the product description/information on both Amazon and the manufacturer's web sites was incomplete and not always correct. The retail box it comes in has some great information on supported RAID configurations.
My suggestion if you have limited disks on-hand at setup, is to only populate the Top Four Slots to make a volume then later on add the remaining Four disks to make up the second volume. This will avoid having to Format your disks to achieve a greater size volume or creating a New volume.Summary: This device came shipped in a very solid packaging similar to an OEM computer case. It was well thought out in that respect. If you have problems in the beginning.
OK. Got all 8 drives in, got it powered up, had all the correct lights on the front panel but the computer refused to see it to initialize it. I assumed based on the doc and on experience that I'd have an indicator if one of the drives was bad. No problem indicators were lit but the computer couldn't see it.I pulled out all the drives and started putting in smaller sets. The computer saw one combination of 4 drives. This says drive problem to me.
The cabinet is nicely made and the controls are fairly intuitive and easy to understand.Installing hard drives is soooo easy. The fan noise is minimal and even adjustable.Unfortunately the USB 3 connection is finicky. I had to make BIOS adjustments on my notebook computer to get the enclosure to connect at USB 3 speeds.It doesn't seem like Mediasonic can or will upgrade the firmware. So unfortunately you might have 8 huge hard drives connecting at USB 2 speeds. That can be a bummer.
I have both the non-Raid and Raid versions of this. The USB 3.0 with a Mac has a few minor issues when drives sleep. They tech support is great though, and I use it with my Mac Pro 1,1 (First Gen Intel one) with a Sonnos USB 3.0 card.
Like I say, not a minutes headache since it's been running 24/7 for almost three months now.The one really useful feature on this enclosure is that it has a loss of power detector via the USB connection that safely shuts the unit off. By simply pulling the USB cable out, it will shutdown and restart similar to the host with No Issues.The Not so Good: During the setup the enclosure driver kept dropping out on me for no good reason.
The customer (dis)Service is only offered through email or forum, the product never stays connected and disconnects when ever it wants, Tech support says &#34;well replace your USB 3.0 cable?&#34;, done that to the point i order some off the net and tried 2.0 none seem to keep it online. Then I started thinking maybe it is some power saving issues, turned those options off and still same thing.
Let me start by saying that I was actually going to return the two ProRaids I bought, and would have left a 1 star rating, if not for some information on the Mediasonic forum.I bought two of this things to setup in 2xJBOD mode each one, width 4x3TB and 4x2TB hard drives on each one, which gives me 12TB and 8TB on each ProRaid.The first problem was actually caused by one of the four WD Reds I bought.
Answer: The RAID processing is on board the ProRAID. The connection to the computer is a standard USB 3.0 or eSATA (multiplier) port.  No special interface card required for USB 3.0.  eSATA must be able to handle multiple drives.