Hardware Aspects and Usage Impressions

The Western Digital My Cloud EX2 is bundled with a 36 W(12V @ 3A) adapter. The power adapter is customized to the country of sale. A network cable is also included in the package. Our evaluation started with a diskless system. Western Digital has diskless, 4 TB, 6 TB and 8 TB systems in the lineup. The systems with disks use two WD Red drives of equal capacity.

Unlike the WD EX4, the hot-swap mechanism is not completely tool-less. After popping open the top of the EX2 unit, a metal flap needs to be unscrewed and the disks need to be pulled out with an attached tag (refer to the pictures in the gallery below). This requires a little bit of force while tugging. Considering that consumers have been taught to treat hard disks as fragile and not to be subjective to excessive force, this is not a pleasant experience. The EX4's hot-swap mechanism and drive-bay arrangement seems to be much better compared to the EX2's, despite the EX2 having what appears to be a better industrial design. The unit has a GbE port, two USB 3.0 ports and a DC power inlet on the rear side of the unit.

There is a very small fan inside the unit (can be seen in the last picture of the above gallery), but it is pretty much inaudible during normal operation.

Platform Analysis

The WD My Cloud EX2 is based on the Marvell ARMADA 370 / MV6710 SoC. We have not reviewed any NAS based on that platform till now. So, we will take a look at the features provided by the ARMADA 370 first.

We find that the SoC provides 4 SERDES lanes, which should be enough for 1 GbE port, two SATA ports and one PCIe lane. The PCIe lane is used by the USB 3.0 to PCIe bridge. Though we didn't get time to do a full teardown and get the part number of the USB 3.0 to PCIe bridge, it is quite likely to be the Etron EJ168A that was used in the EX4. The two SATA ports serve the two drive bays. This configuration seems to provide better balance compared to the EX4 (except for the fact that the two USB 3.0 ports can't both operate at full speeds as the two SuperSpeed ports (10 Gbps) are bottlenecked by the single PCIe 2.0 lane (5 Gbps) connecting it to the ARMADA 370).

Setup & Usage

After connection to the network, the unit obtains a DHCP address (even in diskless mode) and could be setup using the web UI at http://<WD-EX2-IP>.  The UI on the EX2 is the same as the EX4, so we won't go much into the available options in this review. The obvious difference between the EX4 and the EX2 is in the supported disk configurations. While the EX4 can do JBOD, Spanning, RAID-0, RAID-1, RAID-5, RAID-6 and RAID-10, the EX2 can only do the first four.

Our testing sequence started with the insertion of a single disk and configuring it in JBOD. After adding another disk, we were able to migrate to RAID-1. However, the data wasn't online as expected during the process. The resultant RAID volume also appeared to be completely empty. However, creating the same share names as before proved that the data was intact. WD was able to replicate this issue in-house and a fix is expected to be out in one of the upcoming firmware releases. The firmware also doesn't have detailed logs for perusal (this is an issue on the EX4 too).

The EX2 datasheet mentions a limitation of 10 concurrent CIFS connections. In the process of putting the EX2 through our multi-client test (25 machines accessing separate CIFS shares simultaneously), we encountered lots of timeouts (but, the tests did complete after repeated tries). We haven't seen this type of limitation in other 2-bay NAS units (ARM or x86-based). WD indicated that this was more of a marketing positioning of the product. The device apparently does support over 10 users, but the unit is specifically tested considering 10 to be the overall use case for this product. WD suggests that users requiring more simultaneous CIFS connections move to products targeted towards SMBs (those based on the x86 / Windows Storage Server). Though it might be difficult for today's average consumer to hit 10 concurrent CIFS connections, it is not outside the realm of power users with multiple devices in their household.

Introduction Single Client Performance - CIFS and iSCSI on Windows
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  • lours - Tuesday, March 4, 2014 - link

    What is the default setup for the models that come with drives? What capacity are the drives?
  • hlmcompany - Tuesday, March 4, 2014 - link

    As a whole, the unit comes in capacities of 0, 4, 6, and 8 TB. For the units that come with drives, they are the WD Red Drives, such as WD20EFRX, which are slower performing than the 7,200 rpm WD RE4 drives used in this review.
  • ganeshts - Tuesday, March 4, 2014 - link

    Configurations with disks are ready to operate out of the box in RAID-1 configuration. So, a 4 TB model, say, will have 2 TB of usable space.

    As hlmcompany mentions, the WD Red drives are used.
  • chubbypanda - Tuesday, March 4, 2014 - link


    Annoyingly enough, some WD previous models (My Book Studio II) would work only with WD Green drives. Looking at WD's list for EX2, situation is better in this case:

  • Oyster - Tuesday, March 4, 2014 - link

    This review (including some of the other NAS reviews) seems lacking. What's the point of just showing the read/write numbers without giving us the benchmarks. Like why not show us the comparison to Synology and QNAP 2-bay NAS devices? I'd be more informative to see the performance of things like VM images running off these devices as well. I hope this feedback is accounted for in the future reviews.
  • hlmcompany - Tuesday, March 4, 2014 - link

    Agreed. There might even be some relevancy to comparing the My Cloud EX2 with the previous generation model sold as the My Book Live.
  • ganeshts - Tuesday, March 4, 2014 - link

    We have already taken care of that aspect in the multi-client tests. Each graph has a drop-down menu under it that allows readers to view the results from the evaluation of similar NAS units. For example, this review lists other 2-bay NAS units that we have evaluated in a similar manner before. The ioSafe N2 presented as a comparison in this review is the Synology DS213. Unfortunately, we haven't evaluated any 2-bay QNAP units.

    We also have NASPT single-client results for more NAS units. Currently working on a way to integrate a comparison with a drop-down similar to what we have done for the multi-client tests.

    As for VM images, can you clarify the exact use-case? I was under the impression that users mount iSCSI volumes on VMs, and we already present iSCSI performance numbers. (at least, that is what I do with some of my VMs).
  • romrunning - Tuesday, March 4, 2014 - link

    To clarify, the comparisons with other 2-bay NAS are only on the "Multi-Client Performance - CIFS" page. It would have been helpful to have them on the other pages with performance graphs, like the Single-client Windows page. That would make it much easier to compare the different models/vendors.
  • Oyster - Tuesday, March 4, 2014 - link

    Well, mounting the iSCSI volumes is good, but what I meant was to show us the actual comparisons of VM images running from different devices. So a use case would be to do a big Visual Studio compile on a VM over iSCSI on devices from different vendors. All these vendors claim virtualization compliance, so it'd be nice to put numbers against such claims. Data could include network throughput and CPU/RAM consumption, for e.g. This would also help us understand how good some of the Marvell processors are against Atom/x86. As it stands now, the graphs are too confusing...

    Also, as others have pointed out, it's a bit tedious to go clicking through every device from the dropdown and not at all intuitive. If I want to look at HD video playback throughput, I should be able to just look at the line graphs of the different vendors in one chart. Kind of like the video card comparison.
  • creed3020 - Tuesday, March 4, 2014 - link

    I also have to agree that a comparison to other reviewed devices is lacking. This could be in the form of updates to the charts so that they show different units e.g. Video Cards FPS benchmarks, or done verbally within the conclusion or it's own section doing a breakdown of each test.

    These devices are not in Bench so we cannot compare the data there either.

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