diff --git a/tests/qemu-iotests/005 b/tests/qemu-iotests/005
index 2fef63af882ad05708a6cab2f35d67ad4400aba1..9c7681c19bcb0d3046f1983566caa174f52f7d7f 100755
--- a/tests/qemu-iotests/005
+++ b/tests/qemu-iotests/005
@@ -55,6 +55,15 @@ if [ "$IMGPROTO" = "sheepdog" ]; then
     _notrun "image protocol $IMGPROTO does not support large image sizes"
 fi
 
+# Sanity check: For raw, we require a file system that permits the creation
+# of a HUGE (but very sparse) file. Check we can create it before continuing.
+if [ "$IMGFMT" = "raw" ]; then
+    if ! truncate --size=5T "$TEST_IMG"; then
+        _notrun "file system on $TEST_DIR does not support large enough files"
+    fi
+    rm "$TEST_IMG"
+fi
+
 echo
 echo "creating large image"
 _make_test_img 5000G