Mount Synology NAS as Local Drive

Hi all,

I recently purchased a Synology DS418play, which I’m using to back up old files and as a Time Machine backup for my Mac. I know Backblaze won’t back up NASs normally, but is there a way to mount the sinology locally to my Mac via USB? I’ve tried plugging it in using the USB port on the back of the sinology, but so far my Mac doesn’t notice that it’s been plugged it. For what its worth, the Synology also doesn’t know theres a Mac plugged into it.


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With my Drobo, my solution to this was to buy a big, cheap USB hard drive, attach it to my Mac, and use CCC to back up the Drobo to the external HD every week. This gives me both a local backup and allows Backblaze to back the data up to the cloud

As far as I know the USB interfaces at the Synology are being used solely for extending the Synology (e.g. attaching a drive, as I have it for backing up part of the Synology) - you cannot access the file system of the DSM via USB … unless things have recently changed .

But what are you exactly trying to achieve ?

As Sven says you cannot connect Synology
directly with USB, you can though, connect
to Backblaze B2 “directly” with the native DSM
Cloud Sync app.

If not B2, you could automount the DSM shares.
I have had success by using different mount points
than obvious. I.E. Synology Movies share gets mounted as macOS Tax Files (whatever)

Seems to slip under the radar. YMMV

You cannot connect the Synology to your Mac via USB; there is no software on either end to make this connection work.

BackBlaze backup is not designed to allow backups of network shares. You may be able to “fool” BackBlaze by mounting Synology shares to non-standard locations as describe above, but I would be reluctant to rely on that approach in that it is possible for the BackBlaze software to detect such mount points and you might find your backups silently fail at some point. I always want my backup strategies to be reliable.

There is a way to connect the Synology so that it looks like a local disk, and that is to use SCSI over Ethernet. With both your Mac and the Synology on your LAN, you basically make some or all of the Synology storage look like a local drive, via an interface that looks like SCSI, but uses Ethernet as the underlying hardware rather than a (now obsolete) SCSI hardware interface and cable. This is not natively supported by MacOS, and requires software called “SCSI initiator” to be installed on the Mac. There are paid versions available, and I believe free versions as well. The Synology has native support fo this. However, this is probably NOT what you want. The Synology then behaves exactly like it was an external drive attached to the Mac; you format the drive using Disk Utility, and BackBlaze will see it as a local drive and back it up. However, the storage used in this way is NOT a Synology network available share, and cannot be accessed by any machines as a network share; it would be the same as a locally attached USB drive in concept. I don’t think this is what you are looking for.

The best solution I have seen for using BackBlaze backup for network shares is as another poster has mentioned: Attach a USB drive of sufficient size to the Mac, have Carbon Copy Cloner (or similar software) clone the Synology shares of interest to that US drive, and let BackBlaze back up the USB drive.

If you need a more “real time” backup of the Synology share, there are a few solutions. You can do the clone every hour, for instance, although there is a lot of overhead with doing this. You can use another Backup app like Arq, which will handle network shares, and have Arq backup the network share to the target of your choice (including BackBlaze B2, which is what I use), but bear in mind that you pay for storage used with this type of solution, rather than a flat fee for unlimited storage as with BackBlaze backup. You could use the Cloud Sync package on the Synology with one-way syncing of the share to a cloud solution (I use B2 here as well).

Hope this information is of use.


Use the Synology cloud backup app and BackBlaze B2


I am a bit confused: why did you buy a Synology, after all? The Synology you bought is a multimedia cloud solution and I presume that you have loaded it with appropriate drives … it is intended to work as a server, as a pure backup system it is totally underused, imho. If you connect to you LAN you can use it as a service a system, provide access from all internal systems, run the backup on it, use it as a multimedia server, … access it from outside (if you want), … it is a pretty capable system :wink:
Happy to help with the setup, if you want!

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@Sven, you raise a good question. For the OP, it would be helpful to understand your intent in buying a NAS vs a large USB drive if your intent was just archive, storage and TimeMachine.

That being said, I think moving to a NAS can be a very good option for both of these purposes (archival storage and TM) both because it allows you to use said NAS for these purposes for multiple macs (or even windows machines) if you have them; provides this service on the home network which is convenient if you work with a laptop which is more of a nuisance to keep attached to a usb drive for TM; and finally because starting with some simpler uses with a NAS is a good way to get started, and expand into the more complex uses as you gain more experience and see what you need.

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Sorry for going awol on this post. I got this synology for two reasons: redundant back ups of lots of data from Graduate school+Time machine, and to eventually use to set up a VPN. The original reason for the post was trying to get around Backblaze and backing up the synology to them, and avoiding B2.

I mount my Synology drive in my home folder and Backblaze backs it up. The steps are basically:

  1. Make a folder in your home directory where you’ll mount your shared volumes. I made one called ~/mount.
  2. Use the mount_afp command to mount the Synology drive
mount_afp "afp://USER:PASS@SYNOLOGY_ADDRESS/home" ~/mount/synology_home

Instead of entering the password each time, I store it in the keychain. I more or less followed these instructions.

Putting the pieces together, I run more the following script in a Keyboard Maestro macro that runs at log in and every hour.

PASS=$(security find-internet-password -s "NAME OF KEYCHAIN ENTRY" -w)
mount_afp "afp://USER:${PASS}@ SYNOLOGY_ADDRESS/home" ~/mount/synology_home

A few thoughts:

  1. It’s a good idea to mount your Synology share into your home folder to get BackBlaze to back it up. I’m surprised that the BackBlaze software doesn’t check for mounted file systems, though.

  2. It is going to be very important for the server to remain constantly mounted. If the server were to dismount, the /mount folder will appear empty to BackBlaze, causing it to start deletion of the files there in the backup set. When the server remounts, it will start backing them up again. Have you seen this as an issue?

  3. There is a slight insecurity in your code. When you retrieve the password via the security command and save it in an environment variable, your password is now being stored in a potentially accessible way. Secondly, when you execute the mount command using the PASS environment variable, while the mount command is executing, your password would be visible to anyone else logged in to your system (the ps command easily shows all executing commands). This is likely a very minor issue and one that is highly unlikely to be a real security issue for you in practice, but I would NOT use the technique on a shared server, for instance. (There are techniques around it using the expect command, but hardly necessary I would think in your situation.)


I know this is a year old, but does this work still? I tied to test this by mounting a small folder from my NAS and it doesn’t appear to be working. At least BB hasn’t notice the files are there.

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Why don’t you use the Synology Cloud Sync app to sync that folder directly from the NAS to BackBlaze ?

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@lbutlr: If you are mounting a network share, then BackBlaze will not “notice” it. BackBlaze specifically will not backup network shares. It will only work on directly attached storage.

@MacExpert: That’s interesting. I no longer have a Synology, but my recollection was that Synology Cloud Sync works with BackBlaze B2 storage, but not to the BackBlaze backup service (eg the fixed price unlimited storage that is what I assume @lbutlr is referring to).

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There is likely an equivalent application available for that device. I use BackBlaze but their business service.

I was referring to @alexchabot post about how to mount a network share so that Synology would back it up.

Edit: After overnight and logging in to the web interface to check, the answer is that yes, this works. If your NAS is on your LAN, this is a workable solution to back it up to BackBlaze.

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Mount points are one of my favorite things about Unix. Hard drive partition is too small, get a larger on and mount it over the old one. The source of a mount point is hard to trace through software and network agnostic, so I would expect a mount point on the root volume would work, though BackBlaze may have now found a way to ignore mount points of network shares.

Windows is another animal altogether. Windows NTFS 5 appeared to have Unix like mount points, but they are pretty much useless. I don’t know of any reliable way to mount a network volume on a local path.

Windows at least has native iSCSI support. Apple, WHY NOT!?!?!?!?

This appears to no longer be working with Backblaze, or at least for me when I’m trying to set this up for the first time.

When I perform the mount command the drive shows up, but when I go to BB preferences, it shows the drive as not selectable and “unplugged”

Is this just me?

Are you using the Hypercloud backup on the NAS?

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