optimzie virtualAge() a little

pkg/es/ilm_forecast.go

@@ -133,6 +133,7 @@ func IlmForecastShow(conf *cfg.Config) error {
 
 	for _, phase := range phaseData {
 		age := virtualAge(&phase)
+
 		if age < phase.age {
 			age = phase.age
 		}
@@ -142,7 +143,10 @@ func IlmForecastShow(conf *cfg.Config) error {
 		}
 	}
 
-	fmt.Printf("%s bytes of data will be rolled within %s\n", humanize.Bytes(uint64(toBeFreed)), within)
+	fmt.Printf("%s bytes of data in %s phase will be rolled within %s to the next phase\n",
+		humanize.Bytes(uint64(toBeFreed)),
+		conf.Ilm.FromPhase,
+		within)
 
 	return nil
 }
@@ -152,13 +156,7 @@ func virtualAge(phase *PhaseData) time.Duration {
 		return time.Duration(0)
 	}
 
-	oneMinAge := phase.minage.Seconds() / 100
-	oneMinSize := float64(phase.minsize) / 100
-
-	percentSize := float64(phase.size) / oneMinSize
-	virtualAge := percentSize * oneMinAge
-
-	return time.Duration(virtualAge) * time.Second
+	return phase.minage * time.Duration(100*phase.size/phase.minsize) / 100
 }
 
 // Retrieve all index, ilm-explain and ilm-policies in parallel