Unrooted android and SD card


I’d like to begin by saying that Syncthing is probably the best software I’ve used in recent times. Now to the question:

Is syncthing usable in an Android’s SD card? I want to sync music from my laptop/desktop to my android. I’d need the Sync folder to be on the SD card.

I was under the impression that this was not possible, but perhaps there’s some alternative way to make it work?

Best regards,

1 Like

There are several threads and GitHub issue discussing this.

TL;DR: Generally, it is not possible. Syncthing cannot write to the SD card, if it is formatted as mobile storage.

You can format the sd card as internal storage. Then Syncthing can write to it. But you won’t be able to use the real internal storage as storage anymore.

Some OEMs seem to circumvent the restrictions on SD card, as at least one user reports being able to sync the external sd card.

1 Like

What about rooted android? Can syncthing write to an SD card in a rooted android?

It can, but root is unsupported and use-at-own-risk at the moment. There are known isuses, especially when disabling it again.

Most important thing to consider, if you use SuperSU, disable the mount-space separation, otherwise there’ll be a lot of problems.

I guess my best chance is to buy an SD and format it as internal storage… Not sure how that will affect the other apps I use, I will have to try.

Mounting an SD as internal storage will cause /storage/emulated/0 to be on the SD card. All Apps will be non the wiser, everything will work as before.

The SD Card will be encrypted (afaik) and only work in that device.

You should never remove an SD card which is formatted as internal storage.

You should buy a fast SD card. I used a 128GB Samsung card in my Moto X, which was SDXC class 10, and should have 20MB/s write and 80MB/s read. But is was so slow that I had forced reboots all the time.

@wwelch, thank you for all the prompt and informative replies.

Do you know if CyanogenMod supports syncthing on SD cards by default?

i wonder if Syncthing Android could be made the way that TiBackup is to achieve writing to SDcard. i know TiBackup is a root app but i think it doesen’t matter in this case, just read this tutorial:

That’s the proper solution, but unfortunately not supported by Golang at this point.

1 Like

[quote=“jackson, post:1, topic:8546, full:true”] Is syncthing usable in an Android’s SD card?[/quote]

Maybe this depends on the version of Android? In my naivety I set up syncing a folder on an external SD card on one device. This has worked without a hitch for months. The device uses Android 4.2.2

Right, Android 4.3 and lower works fine.

Does Syncthing work fine (using an SD card) in the latest versions of CyanogenMod?