diff --git a/weed/util/limited_pool.go b/weed/util/limited_pool.go
new file mode 100644
index 000000000..91499632c
--- /dev/null
+++ b/weed/util/limited_pool.go
@@ -0,0 +1,40 @@
+package util
+
+// initial version comes from https://github.com/korovkin/limiter/blob/master/limiter.go
+
+// LimitedConcurrentExecutor object
+type LimitedConcurrentExecutor struct {
+	limit     int
+	tokenChan chan int
+}
+
+func NewLimitedConcurrentExecutor(limit int) *LimitedConcurrentExecutor {
+
+	// allocate a limiter instance
+	c := &LimitedConcurrentExecutor{
+		limit:     limit,
+		tokenChan: make(chan int, limit),
+	}
+
+	// allocate the tokenChan:
+	for i := 0; i < c.limit; i++ {
+		c.tokenChan <- i
+	}
+
+	return c
+}
+
+// Execute adds a function to the execution queue.
+// if num of go routines allocated by this instance is < limit
+// launch a new go routine to execute job
+// else wait until a go routine becomes available
+func (c *LimitedConcurrentExecutor) Execute(job func()) {
+	token := <-c.tokenChan
+	go func() {
+		defer func() {
+			c.tokenChan <- token
+		}()
+		// run the job
+		job()
+	}()
+}
diff --git a/weed/util/limiter.go b/weed/util/limiter.go
deleted file mode 100644
index 9d63c12a1..000000000
--- a/weed/util/limiter.go
+++ /dev/null
@@ -1,114 +0,0 @@
-package util
-
-import (
-	"math/rand"
-	"reflect"
-	"sync"
-	"sync/atomic"
-)
-
-// initial version comes from https://github.com/korovkin/limiter/blob/master/limiter.go
-
-// LimitedConcurrentExecutor object
-type LimitedConcurrentExecutor struct {
-	limit     int
-	tokenChan chan int
-}
-
-func NewLimitedConcurrentExecutor(limit int) *LimitedConcurrentExecutor {
-
-	// allocate a limiter instance
-	c := &LimitedConcurrentExecutor{
-		limit:     limit,
-		tokenChan: make(chan int, limit),
-	}
-
-	// allocate the tokenChan:
-	for i := 0; i < c.limit; i++ {
-		c.tokenChan <- i
-	}
-
-	return c
-}
-
-// Execute adds a function to the execution queue.
-// if num of go routines allocated by this instance is < limit
-// launch a new go routine to execute job
-// else wait until a go routine becomes available
-func (c *LimitedConcurrentExecutor) Execute(job func()) {
-	token := <-c.tokenChan
-	go func() {
-		defer func() {
-			c.tokenChan <- token
-		}()
-		// run the job
-		job()
-	}()
-}
-
-// a different implementation, but somehow more "conservative"
-type OperationRequest func()
-
-type LimitedOutOfOrderProcessor struct {
-	processorLimit     int32
-	processorLimitCond *sync.Cond
-	processorSlots     uint32
-	processors         []chan OperationRequest
-	currentProcessor   int32
-}
-
-func NewLimitedOutOfOrderProcessor(limit int32) (c *LimitedOutOfOrderProcessor) {
-
-	processorSlots := uint32(32)
-	c = &LimitedOutOfOrderProcessor{
-		processorSlots:     processorSlots,
-		processors:         make([]chan OperationRequest, processorSlots),
-		processorLimit:     limit,
-		processorLimitCond: sync.NewCond(new(sync.Mutex)),
-	}
-
-	for i := 0; i < int(processorSlots); i++ {
-		c.processors[i] = make(chan OperationRequest)
-	}
-
-	cases := make([]reflect.SelectCase, processorSlots)
-	for i, ch := range c.processors {
-		cases[i] = reflect.SelectCase{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(ch)}
-	}
-
-	go func() {
-		for {
-			_, value, ok := reflect.Select(cases)
-			if !ok {
-				continue
-			}
-
-			request := value.Interface().(OperationRequest)
-
-			if c.processorLimit > 0 {
-				c.processorLimitCond.L.Lock()
-				for atomic.LoadInt32(&c.currentProcessor) > c.processorLimit {
-					c.processorLimitCond.Wait()
-				}
-				atomic.AddInt32(&c.currentProcessor, 1)
-				c.processorLimitCond.L.Unlock()
-			}
-
-			go func() {
-				if c.processorLimit > 0 {
-					defer atomic.AddInt32(&c.currentProcessor, -1)
-					defer c.processorLimitCond.Signal()
-				}
-				request()
-			}()
-
-		}
-	}()
-
-	return c
-}
-
-func (c *LimitedOutOfOrderProcessor) Execute(request OperationRequest) {
-	index := rand.Uint32() % c.processorSlots
-	c.processors[index] <- request
-}