Western Digital My Cloud EX4 NAS device (preview)

With the EX4, WD sets its sights on power-users and the SOHO/SMB market.

In early November, Western Digital launched its single-bay My Cloud ‘personal cloud storage system’. Where the basic My Cloud is essentially an external hard drive that you can access via the internet, the four-bay My Cloud EX4 is a full-fledged NAS device with all the specs and features you’d expect thereof.

Despite its additional feature set, the My Cloud EX4 aims to keep the same consumer-level ease of use as its smaller sibling. It’s also designed to deliver the same ‘ready to go, straight out of the box’ experience, if you buy one of the units pre-populated with WD Red hard drives.

8TB, 12TB and 16TB versions are available – see pricing at the end of this preview. For those wishing to use alternative drives, a drive-less, unconfigured version is also available.

Down tools

Unlike the majority of four-bay NAS devices we’ve seen, the EX4 has not only toolless drive bays (you don’t need a screwdriver to swap hard drives), but caddyless bays. Instead of being mounted into plastic caddies and slid into the enclosure, you just open the drive bay door and the hard-drive pops out on its own.

The EX4’s design is only marginally more convenient than using toolless caddies – it’s not every day that you swap out drives – but there’s a hidden secondary advantage here. Over years of testing, we’ve found that the slide-out plastic caddies used by most NAS enclosures are the most breakable part of the whole setup.

The My Cloud EX4 has four toolless, caddyless 3.5-inch drive bays.
The My Cloud EX4 has four toolless, caddyless 3.5-inch drive bays.

We’ve scrapped entire consumer NAS systems because a couple of the caddies broke, and it was prohibitively expensive to get replacement hunks of plastic. Simplifying the drive bays while still leaving the drives hot-swappable is a great idea, and from our brief look at the EX4 during WD’s launch event, the company seems to have nailed it.

Ready to go

If purchased pre-configured with WD Red hard drives, the My Cloud EX4 ships ready-to-go. The idea is that you connect it to your home or office network via Ethernet; install the app on your iOS or Android device, or the desktop software on your PC or Mac; and the default shared folders are sitting there ready for you.

Whether it really is this simple remains to be seen – it is (by necessity) the first thing we’ll test when the EX4 arrives in our offices for review.

Remote access is supposed to be similarly simple to configure – that’s the root of the ‘private cloud’ branding Western Digital is using on the My Cloud products, after all.

Like the single-bay EX4, this really is just an easily-internet-accessible NAS setup – none of your data is stored ‘ in the cloud’ in the public-cloud sense. The My Cloud products are no more ‘private cloud’ solutions than any NAS device, but we’ll forgive the vaporous branding if the functionality pans out as advertised.


The MyCloud EX4 sports dual Gigabit Ethernet ports, for high-speed network connectivity. This is truly useful, as it’s possible to max-out a gigabit connection with file transfers fairly easily. One gigaBIT per second is only about 0.12 gigaBYTES per second, or 125MB/sec.

With multiple hard drives in RAID, it should be possible to reach write speeds near that figure, and max out one of the Ethernet interfaces with just a single large file transfer. Hence, if you’ve got a high-capacity router, it’s a great idea to hook up both ports and take advantage of the increased throughput.

That’s the theory of it, anyway – something else to verify on the testbench.

For external storage – either as expansion or to facilitate on-site backup, the EX4 has a pair of USB 3.0 ports. Performance will depend on the external drives you connect, which will top-out in speed long before the USB 3.0 port’s capacity is tested.

Most interestingly (though arguably, least usefully), the My Cloud EX4 has twin power inputs so you can connect two separate AC adapters. Only one adapter is included in the box, but a second can be purchased as an optional extra – price to be confirmed.

Everything is doubled up -- dual Gigabit Ethernet ports, dual USB 3.0, and even dual power-supply support (though only one power adapter is included).
Everything is doubled up -- dual Gigabit Ethernet ports, dual USB 3.0, and even dual power-supply support (though only one power adapter is included).

The dual-power system is for redundancy only – only one adapter is required to supply power to the unit, and there is no other advantage to connecting two. This guards you against power supply failure, and power adapters do fail now and again – particularly on always-on devices such as routers or – potentially – NAS devices. However, we’d wager that you’re far more likely to suffer a regular power outage, or something like a surge, than a random power supply failure.

Where the dual-supply does come in truly handy is if you connect each power adapter to a separate circuit in your home or office – if one has a fuse blow, or or has to be turned off for maintenance, power to the NAS remains uninterrupted. This is sever-level stuff (it is, in fact, how most server-room network and computer gear is designed) – however, it’s highly unlikely that the average home or office would be set up for this.

Getting complicated

Though it offers the same simple mobile-app and desktop-application access as the single-bay My Cloud, the EX4 adds the usual range of advanced features you should expect from a SOHO/SMB-grade NAS device. The advanced features are configured through a web interface, which is similar to but expanded from the basic interface on the My Cloud.

User accounts and user groups can be used to control access to file shares (the single-bay version does include this feature), with each user issued a 12-digit code that can be entered to allow them remote access from the mobile or desktop apps.

Users may be assigned quotas to control disk usage.

RAID 0, 1, 5, 10 and JBOD are supported, with a default configuration of RAID 5 (striping with parity). The EX4 supports ‘disk roaming’ – all configuration data is stored on the disks themselves, so set of hard drives may be swapped from a faulty enclosure to a new one of the same model, and be booted up and used exactly as before.

Volume encryption is available, which the single-bay device does not support. Depending on the data stored, this can be critical for ensuring that data is inaccessible if the NAS and its drives are stolen. If you’re just using the EX4 to store your movie collection, it may be better to avoid encryption and take the improved read/write performance instead. We’ll be testing the performance impact of encryption for our review.

The EX4 can backup its contents automatically to Amazon S3.

The EX4 can backup its contents automatically to a connected USB hard drive, remotely to another My Cloud EX4, or online to Amazon S3 or Elephant Drive. Other online backup services may be added in future.

Western Digital has released a software development kit (SDK) for the EX4 , that allows developers to create apps to run on the NAS. Existing apps include the popular Twonky Media Server, Wordpress blogging platform, Joomla CMS, phpBB bulletin board, and phpMyAdmin management tool for MySQL.

iTunes server functionality, and HTTP/FTP/Torrent download apps are built in. We haven’t seen the full app catalogue, so we can’t yet compare its size to those of competitors such as Synology, QNAP or ASUSTOR. However, Western Digital’s market presence should make it easy for the company to attract developers to its My Cloud platform.


Read more: Western Digital My Passport Wireless (2TB) review

If the My Cloud EX4 is as easy to set up as it claims, without compromising its power-user functionality, it could present an attractive competitor to existing home/SOHO NAS systems.

Remote access is one of the most useful features offered by NAS, but often one of the most difficult to configure and one of the least reliable. We look forward to seeing whether WD has overcome these obstacles with the EX4, which would give it a real point-of-difference in the network storage market.

Australia/New Zealand pricing for the My Cloud EX4 is as follows:

ModelCapacityAustraliaNew Zealand
WDBWWD0000NBKNo drives$600$700

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Tags private cloudstoragewestern digitalWDmy cloud

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Harley Ogier

Harley Ogier

PC World New Zealand
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