prevent filling up the disk

README.md

@@ -62,6 +62,11 @@ transbeam is configured with the following environment variables:
   case-sensitive.)
 - `TRANSBEAM_MAX_STORAGE_SIZE`: maximum total size of all files being
   stored by transbeam (default: 64G)
+- `TRANSBEAM_MIN_DISK_FREE`: minimum amount of free disk space on the
+  filesystem where transbeam uploads are stored (default: 8G).
+  transbeam will not accept uploads that would reduce free disk space
+  lower than this value, even if they would otherwise be within the
+  max upload size and max storage size.
 - `TRANSBEAM_MNEMONIC_CODES`: generate memorable download codes using
   English words, rather than random alphanumeric strings (default:
   true)