rebalance: use -metrics-per-second for reset

Before this change, if go-carbon health check is enabled, when go-carbon cache.size overflows, buckytools
reset sync speed to 1 metrics-per-second and there is no way to adjust it. This is not ideal if a go-carbon
box always has cache.size limit over the safty threshold due to file system fragmentation or aging ssd.

With this change, it allows to have an adjustable minimum sync speed.

Author: bom-d-van

buckytools.go

@@ -2,7 +2,7 @@ package buckytools
 
 const (
 	// Buckytools suite version
-	Version = "0.4.2"
+	Version = "0.5.2"
 )
 
 // SupportedHashTypes is the string identifiers of the hashing algorithms

cmd/bucky/common_sync.go

@@ -492,11 +492,11 @@ func (ms *metricSyncer) newGoCarbonState(addr string, speedUpInterval int) *goCa
 		for {
 			select {
 			case <-state.fastReset:
-				atomic.StoreInt64(&state.metricsPerSecond, 1)
+				atomic.StoreInt64(&state.metricsPerSecond, mps)
 				speed.Reset(time.Second / time.Duration(state.metricsPerSecond))
 			case <-speedUp.C:
 				if ms.isGoCarbonOverload(state) { // overload check
-					atomic.StoreInt64(&state.metricsPerSecond, 1)
+					atomic.StoreInt64(&state.metricsPerSecond, mps)
 				} else if !ms.flags.noRandomEasing &&
 					atomic.LoadInt64(&state.metricsPerSecond) >= 30 &&
 					rand.Intn(10) <= 2 { // random easing