How to make incremental, differential backups from NAS to external USB

I recently purchased a PR4100 to replace / upgrade from a pretty old low-end Netgear 2-bay NAS. Overall, I am quite satisfied with the performance of the unit. I’m not doing anything terribly complicated or sophisticated with the NAS: it’s basically used as a common data repository for files shared between two computers on my home network and as a primary backup location for files from those computers (using Resilio Sync, for which I already had a home Pro license.) Although most of the content on the NAS is media (photo, video, music) I have not set it up as a media server as yet and don’t know whether I will or not (primarily because PLEX lacks Adobe Lightroom integration, which makes it unsuitable for my needs.)

Given my simple needs, I was not overly concerned with the lack of sophistication and options I found available with the My Cloud firmware, especially when compared with Netgear. However, one thing I found it could not do, which I could on the Netgear, was create scheduled and managed backups from the NAS to an external USB drive (I have been using WD Passport drives for this). I find this to be a glaring weakness of the WD offering. Searching through the forums I found solutions that involved creating scripts and cron jobs, which, although I am capable of tackling, I would prefer a much simpler solution (and obviously one that is baked into the firmware.)

I have found a couple of solutions to this problem in a Windows environment (and i’m betting similar options can be found in the Mac world) using off-the-shelf software; some freeware and some not. I thought I would pass on some of my experiences for those who are interested in exploring these and other similar products as solutions for your needs.

First of all, I already had set up some of the folders I wanted to back up from the NAS in two different ways for accessing them from my computer:

  • One was to map a folder within the public share on the NAS as a network drive on my computer (WD has easy to follow instructions if you need them on the support site).
  • The second was to create a symbolic link to a folder on the NAS and place it in my user directory (I use Link Shell Extension:

Many of the backup software products I tried were not capable of backing up from or to network locations; be they shares, mapped drives, or linked locations.

Of the several software solutions I tested, I found only one - Aomei backupper (google it) that could recognize the NAS as both a source and destination location for backups. It can do scheduled, incremental backups.
It has a lot of other capabilities (system backups, partition backups) that are outside the scope of this discussion, but which make it useful for other needs. The only thing that made me pass on Aomei as the solution of choice is that creating a backup scheme (how many versions to keep, when to delete, etc.) are not available in the free version and I wasn’t ready to pay for a solution when I had a no additional cost solution at hand (see below.) That means that if you’re doing incremental backups, at some point manual intervention is required or you just have one full backup and a never-ending series of incremental backups.

If I were satisfied to have a full backup only, the solution I would consider is Cobian Backup. It can see the NAS and the USB drive as network locations, it can do scheduled backups and it has the advantage of being able to see the backed up files directly from Windows, which means you don’t really need a restore function, because you can just copy files back to wherever with native Windows functionality. It cannot do incremental or differential backups. The thing that steered me away from living with these limitations was that one of the directories I want to back up is huge and creating full backups each time seemed wasteful. Also, the product site has been taken over by a new owner and this could make the future of the software uncertain.

The solution I landed upon occurred after a facepalm while wishing I didn’t have to pay for getting what I really wanted. I realized I already had something in hand that would work. I am currently using CrashPlan for my cloud backups. CrashPlan has the option to do backups to a local location and has the capability of backing up from and to mapped (and symlinked) network locations. It can do scheduled and managed backups.

Obviously, this is not the answer for everyone, but if you already have a some sort of backup solution in hand, it would be worth checking out whether it can accomplish closing the gap that WD has left in it’s backup capabilities in My Cloud.

FYI there is a dedicated subforum for the PR Series. This subforum (My Cloud) generally discusses the single bay/single drive My Cloud units.

The PR Series has an embedded backup feature in the My Cloud Dashboard. It allows one to backup the My Cloud to either a USB drive attached to the My Cloud or to another location. See Chapter 8 Backing Up and Retrieving Files in the PR Series User Manual (

One can also use Rsync to backup files to USB hard drive attached to the My Cloud or to another network location. I use a variation of the methods discussed in this thread:

For backing up a My Cloud to a USB drive attached to my computer(s), while one can use a dedicated backup program, I ended up using Free File Sync ( and mirroring the files to a USB drive attached to another computer on the local network. That program is free and pretty simple to setup and configure.

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My bad: I figured this forum was for the firmware. The situation I am talking about applies to more than just the PR series.

From WD Support on Configuring USB Backups:
NAS to USB Incremental Backup is not supported
Scheduled USB Backup is not supported

A main point of my post was wanting to avoid having to create scripts and jobs, which can often be beyond the skill set of some users.

The missing scheduled USB back is a common complaint with the v2.x firmware going back years. Few examples in the Cloud Ideas subforum.

The first generation v4.x single bay My Cloud does offer scheduled backups (called Safepoints) in the My Cloud Dashboard. For what ever reason WD decided not to include a scheduler in the newer v2.x firmware for various My Cloud models. This of course has forced (we) the end users to find workarounds which sometimes involves using computer based backup software to accomplish what should be a standard feature with My Cloud firmware.

The main problem with using software on a PC to backup to a USB drive attached to the My Cloud is data may end up flowing from the My Cloud through the computer then back to the My Cloud then to the USB drive attached to the My Cloud. Resulting in a very slow backup.

While I used to use Safepoint to backup my first gen single bay My Cloud, I’ve found it sometimes failed to backup properly. That’s why I switched to using Rsync. More control over how and what I backup. Yes it takes a little bit of Linux knowledge and SSH knowledge to setup and enable Rsync backups, but the end result is the backup goes from the My Cloud to the USB drive without going onto the network. Even though the USB port on the single bay My Cloud is a bit slow its better than sending the data across the network then back. But as always YMMV.