Hello everyone, I have a huge issue with Syncthing and data scrambling.
A brief overview over my systems involved in this issue:
- PC, Manjaro, Syncthing 1.2.0
- Home Server, Arch Linux, Syncthing 1.2.0
- Notebook, Arch Linux, Syncthing 1.2.1 (!)
- Multiple other devices like Android phones and Linux laptops I am pretty sure have nothing to do with this issue
On August 15, 2019 I did a full system update including Syncthing 1.2.0 -> 1.2.1 on my notebook. Context: I was not at home so there was no connectivity to the other devices.
After a reboot I noticed 100% CPU load for some time but ignored it as this is what usually happens after a Syncthing update sometimes when it is rebuilding its index.
When the CPU load did not reduce after quite some time I checked the Syncthing web interface and it showed “Scanning” on the first folders and all folders below showed the state “Unknown”. The systemd journal did not show anything I could Identify as abnormal at first glance.
I stopped Syncthing as I had other things to do at that moment. The next day when I started my notebook again there was 100% CPU load. I stopped Syncthing again as I was at customer site and had no time for debugging. I came back home and started my notebook and simply let it run for an hour. When I came back it was still running on 100% CPU load and the web interface still showed “Scanning” on the first folders and “Unknown” on the others. This definitely did not look normal.
I checked the folders on my notebook and at first glance they looked OK. But when I checked the folders on my home PC and my Home server I discovered something really bad. All Syncthing folders had lots and lots of directories and files from all other Syncthing directories scrambled into them. Files and directories definitely only present in one Syncthing directory before appeared in almost all other directories as well.
I immediately stopped Syncthing on my notebook and the Synchronization craze stopped and all Systems came to a stable state (besides the fact that I have “Out of Sync” messages on many folders…).
This is the current state. On my other computers and phones the synchronized folders are all scrambled up badly, on my notebook only a couple of directories and files seem to have been scrambled.
I am pretty sure my notebook is the issue with Syncthing 1.2.1. I have never had issues with Syncthing especially not as bad like these.
Fortunately I have backups of most of the data so I will eventually be fine but at the moment this is a huge issue as the synchronized data is in the scale of terabytes in about 30 directories. Also I do know how to proceed with my notebook. Will the craze continue when I update my other devices? Did anyone hear of such an issue before? What is the cause? How can I debug it? How can I avoid this issue in the future?
Maybe someone has an idea on any of the questions.