diff --git a/scripts/volume-backup.sh b/scripts/volume-backup.sh
index 49e3bce..1dbc06e 100755
--- a/scripts/volume-backup.sh
+++ b/scripts/volume-backup.sh
@@ -8,7 +8,7 @@ function log() {
     echo "[$(date -Iseconds)] $*" | tee -a "$LOG_FILE"
 }
 
-MODE="${1:-cold}"
+MODE="${1:-}"
 if [[ "$MODE" != "cold" && "$MODE" != "hot" ]]; then
     log "usage: $0 [cold|hot]" >&2
     exit 1