[Syncthing on ARM router] index-db files no space left on device


I am running Syncthing for ARM 1.1.0 on a Linksys WRT32X (ARMv7) router with OpenWRT 18.06.02 in it.

Everything works fine (installation, configuration, gui…) but whenever I try to sync a folder, the local folder on my router


gets fastly populated by *.ldb files that leaves me out of free space on my router and I keep getting the following error:

FATAL: Error opening database: write /root/.config/syncthing/index-v0.14.0.db/0000XX.ldb: no space left on device.

Is there any way to either limit the local space ldb files can take on my router or to create a symlink to an external drive?

Thanks in advance.


Syncthing stores data like configuration, keys and the index database in it’s home folder, which defaults to $HOME/.config/syncthing.

Since space on your router seems to be severly limited, I would suggest moving the entire config directory to a different drive. You can do that by shutting down syncthing and manually copying the directory to it’s new place.

Afterwards, check how to change command line options on OpenWRT. You want to set the -home flag, where you can specify the new path to the folder.

For more information, see the docs here: https://docs.syncthing.net/users/config.html


Thank you, it sounds pretty straightforward to do.

I will use a spare pendrive attached to the other USB port on my router to store the config folder.

Do you happen to know how big should it be to hold a 2TB sync? I mean, if there is some estimated size for the ldb files on the db folder.

Thanks in advance.


I’ve no idea how the database grows, but I’ve been syncing around 200 Gigabytes with about 188k files in 20k folders for about a year and my database is currently 389 Megabytes big. Maybe resetting it from time to time will shrink the size down, I’ve added and removed folders a lot through time and I don’t know how good the database is with cleanups.

So if you want to play it save, have some gigabytes free for the database.

(Evgeny Kuznetsov) #5

I remember @AudriusButkevicius mentioning some formula like “X bytes for every block times number of devices times something else”, but I can’t seem to find this quote.

(Simon) #6

Also see -home: https://docs.syncthing.net/users/syncthing.html#cmdoption-home

DB size scales with amount of files and external devices.

And my own potentially off estimation would be 8kB * files * devices with large blocks enabled.


Thank you all.

I have a 4GiB pendrive that I guess it will be enough.

I will bump the thread if not :slight_smile: