This is on an Odroid HC2, root drive is a 32GB micro SD card, with a 4TB SATA data drive connected.
When trying to install some extra plugins (shellinabox, for example) I'm getting a "No space left" error (28).
I'm not sure what or how the root partition is getting used up. I'm including screenshots showing the storage disks, and partitions. The data drive is LUKS encrypted.
Below is what I get with the du command on the root folder.