diff --git a/lib/flagutil/duration.go b/lib/flagutil/duration.go
index dd80d2cbc..61b5f414f 100644
--- a/lib/flagutil/duration.go
+++ b/lib/flagutil/duration.go
@@ -14,7 +14,7 @@ import (
 //
 // DefaultValue is in months.
 func NewDuration(name string, defaultValue string, description string) *Duration {
-	description += "\nThe following optional suffixes are supported: s (second), m (minute), h (hour), d (day), w (week), y (year). " +
+	description += "\nThe following optional suffixes are supported: s (second), h (hour), d (day), w (week), y (year). " +
 		"If suffix isn't set, then the duration is counted in months"
 	d := &Duration{}
 	if err := d.Set(defaultValue); err != nil {