Use

You may install any type of SATA hard drive in there. As both docks work independently, you may plug in two different sized drive or ones of different capacity and speed. If you would like to use the RAID features, it is a general recommendation that two identical storage devices are used. We will be using two Hitachi 500GB 7200 RPM Drives with 16MB cache to see what the Zalman ZM-200 U3 is capable of. While we could have gone ahead and used two high-end SSDs, I do not see such a configuration as being the mostly used one, thus we will focus on traditional hard drives instead.


Once the drives are plugged in, the unit is up and running and you access one or both of them, the blue LED to the left of each bay lights up accordingly. Besides that there is no traditional power LED. Zalman does mention that the device will enter a standby mode after 10 minutes of inactivity to save power and prolong the lifetime of the drives.

Performance

USB 3.0

Single Drive/JBOD

When just a single drive has been installed, we are seeing this downward curve. This means that the single drive never manages to max out the capability of the Zalman MH200 U3. You can expect to see the same performance as when the drive is connected to eSATA or plugged straight into the SATA port of your mainboard.


JBOD simply means "Just a Bunch Of Disks". In this configuration, the two installed drives appear as one big unit in Windows. As you can see in the graph above, the performance result is just two curves - each similar to the single disk performance. So you do not have any benefits besides the fact that only one drive letter is used and all files appear to be on one source in the operating system.

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Write performance also maxes out with the drive and not the USB 3.0 interface - just as you would expect

RAID 1

Besides being able to utilize two drives - which is a feature available for many other such docking stations, the Zalman MH200 U3 also allows you to configure the drives in RAID 1. This means that the contents of one drive is mirrored unto the second one, resulting in loss of half the storage - in our case we are able to use 500GB while the other 500GB are used to store a 1:1 copy of the source drive. At this point the performance is as expected, very similar to what you would see on a single drive.


The write performance drops just a tiny bit as data is also written to the second drive. But this drop in performance is less than 1% so you should not notice anything in real world applications.

RAID 0

Now this is where it gets really interesting, as RAID 0 runs both drives in parallel, bundling the performance of the drives. The downside of such a configuration is the lack of data security. If one drive breaks or is removed, the RAID array is lost completely. We will leave ATTO out of this part, as we can see the maximum performance of the enclosure in this graph. Theoretically speaking, with one drive achieving 130 MB/s read and write, the performance should double. As you can see in the graph above, we hit a ceiling in both read and write performance and are thus able to max out the Zalman MH200 U3. Just above 200 MB/s read performance along just above 160 MB/s maximum write speed is very good for an external enclosure, but nowhere near what the drives are capable of in RAID 0 connected directly to SATA.

USB 2.0

I used the two hard drives push the enclosure to its limit while connected to USB 2.0. The performance is excellent with 36.6 MB/s and thus one of the best performance we have ever seen on a USB 2.0 connection. The write speed is more down to earth, but still very good with just above 30 MB/s.