I sync my phone camera folder (3400 files / 34GB) and have a very slow sync from android to windows.
Slow means that syncing takes forever. I have the impression it can do fast transfers (up to 100MBit/s), but there are really long gaps where nothing happens and transfer rates go down to 0.
I have read about the problems with the android storage interface, however I understand here the problem is mainly with receiving many small files and store them on the phone. My main use case is uploading from phone to PC. After vacation, uploading the ~1GB new photos takes hours.
What I tried:
Change to the new syncthing fork → same issue
sync to a Windows and a Linux client on my PC → no difference
sync between windows + Linux client → after hours of sync from phone → Windows, I start the linux client and the same amount syncs between minutes.
Further infos:
phone: Pixel 7a with android 15
path to the shared folder on android: /storage/emulated/0/DCIM
all clients are in the same LAN (connection type: TCP LAN)
GSAM battery monitor shows huge runtime on job/com.google.android.providers.media.module/com.android.providers.media.MediaService
While the camera sync is stalling, a different folder can upload 200MB in a few seconds.
Not really, the known problem is that syncing to Android will be slow if you’ve got thousands of files located in the same folder, however, the other way around, there should be no issues.
Can you post screenshots of the Syncthing Web GUI from both sides? Please make sure that the information under “Remote Devices” is visible. On Android, you can access the Web GUI from the left slide-out menu.
I was worried that your devices might be connected via a relay, which could cause the slow sync, however it doesn’t seem to be the case. Not sure whether it will have any effect on the issue at hand, but you seem to be still using the now deprecated official Syncthing for Android app, so I’d like to suggest switching to Syncthing Fork, which is kept being updated. You can transfer your current config to it (see https://github.com/Catfriend1/syncthing-android#switching-from-the-now-deprecated-official-version).
Came here just to say “me too” and hopefully include useful data. I was running Syncthing-Fork and was trying to sync photos from Android to a computer on my local network. Details:
Syncthing Fork version 1.28.1.1
Connection type is always “TCP LAN”, run mode is wifi only
Folder is /storage/emulated/0/DCIM
Contains 3278 photos/videos, 72 GB of data
Let it run for 24 hours and it still was only half done before I killed it
It would consistenly wait for long periods of time with 0 B/s upload speed, then have little bursts of 1 MB/s upload for a second, then stop
So I took the advice of alswkd4 and installed Syncthing 1.9 from the link he sent and it worked like you’d expect:
Remaining 40 GB or so synced in about 30 minutes
Maintains consistent 20-30 MB/s upload speed
So something definitely changed in later versions of syncthing for android that caused an extreme loss of performance for this use case.
Note that I’ve been using the recent version of Syncthing Fork to sync other things to/from Android (also under /storage/emulated/0) without problems. So it’s something about the quantity or size of the photos folder.
I’m having the exact same problem, except it occurs with every folder I try to sync. None of the solutions I’ve found online fixes it.
Using the old version mentioned above doesn’t fix the problem for me.
Syncthing used to work perfectly with just basic setup. Now it’s suddenly become useless.
Hopefully a proper fix comes out, I’m going to have to go back to connecting my phone to the computer via USB and using adb (ugh).
I have the same issue with a Poco F6 on Android 15. Before with my Mi9Lite on Android9 it was running perfectly fine. Now syncing is practically impossible because it hangs on 63% with speed 0b/s. I switched to the syncthing forc..no luck now and I wonder how I could handle my files now… ; One post says switching back to version 1.9 should work. But then this would mean that the “error” would be in Syncthing not on Android 10+. So now I’m helpless here… maybe try to copy by USB cable… poor solution…
Hi Catfriend1, I just did some testing and got these results.
Steps:
Full uninstall, not keeping data
Install
Restore backup settings
Force start, ignore run conditions
2300 files: 100GB~
1.26.01.00 - Fast
1.27.06.00 - Fast
1.27.12.00 - Fast
1.28.00.00 - Slow
1.28.01.00 - Slow
1.28.01.01 - Slow
1.30.00.01 - Slow
Fast - Stable transfer speed from Android -> Windows (11-13MB/s)
Slow - Burst of speed for a second, then 0 for minutes at a time. The speed drop-off happens almost immediately after sync starts.
Android 15
1.27.12 has been stable while I typed this reply. I hope this helps narrow it down.
I tried this version as suggested by @alswkd4 and it really is working exceptionally well. In my case I’m syncing two Android devices (WhatsApp folder to be specific) where I have installed the 1.9.0 Version and it’s not getting stuck at all. Thanks a lot for this suggestion. Moreover, it is scanning the files fast as well.
Hello @Catfriend1 , I’m also facing this issue. I’m trying to sync my mobile and tablet data in windows machine. Yesterday, I’ve downloaded app from play store, It worked fine in my tablet where only 45MB data needed to be synced in windows but when I installed in my phone where I needed to sync around 64GB data then it is not getting synced, speed is immediately dropped and sync is stuck 74MB. Seems like some issue when data is huge. I can wait for fix tough if you are releasing in play store, will update app from play store once you release fix. Just let me know if you are working on it, otherwise will try to use 1.9.0 version, seems like it is working for folks(although I haven’t tried it).
It’s still slow for me. I even tested out 1.27.12.00 where I got slowness. But this is even the case with the last version of the syncthing app for android (non-fork).
The only version that worked as expected for me was the 1.9.0. Even the scanning of the folder is faster in 1.9.0 compared to the 3-4 versions I tested.
I read somewhere that this might be caused because of not using the Media Picker but I’m not sure.
Edit - I will try to start the test from 1.9 onwards to see where it started happening and will provide the details.
