diff --git a/weed/filesys/dirty_page.go b/weed/filesys/dirty_page.go
index 871905fd5..c69851071 100644
--- a/weed/filesys/dirty_page.go
+++ b/weed/filesys/dirty_page.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"sync/atomic"
 	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
@@ -21,12 +22,6 @@ type ContinuousDirtyPages struct {
 	lock    sync.Mutex
 }
 
-var bufPool = sync.Pool{
-	New: func() interface{} {
-		return new(bytes.Buffer)
-	},
-}
-
 func newDirtyPages(file *File) *ContinuousDirtyPages {
 	return &ContinuousDirtyPages{
 		Data: nil,
@@ -37,9 +32,14 @@ func newDirtyPages(file *File) *ContinuousDirtyPages {
 func (pages *ContinuousDirtyPages) releaseResource() {
 	if pages.Data != nil {
 		pages.f.wfs.bufPool.Put(pages.Data)
+		pages.Data = nil
+		atomic.AddInt32(&counter, -1)
+		glog.V(3).Infof("%s/%s releasing resource", pages.f.dir.Path, pages.f.Name, counter)
 	}
 }
 
+var counter = int32(0)
+
 func (pages *ContinuousDirtyPages) AddPage(ctx context.Context, offset int64, data []byte) (chunks []*filer_pb.FileChunk, err error) {
 
 	pages.lock.Lock()
@@ -47,15 +47,17 @@ func (pages *ContinuousDirtyPages) AddPage(ctx context.Context, offset int64, da
 
 	var chunk *filer_pb.FileChunk
 
-	if pages.Data == nil {
-		pages.Data = pages.f.wfs.bufPool.Get().([]byte)
-	}
-
-	if len(data) > len(pages.Data) {
+	if len(data) > int(pages.f.wfs.option.ChunkSizeLimit) {
 		// this is more than what buffer can hold.
 		return pages.flushAndSave(ctx, offset, data)
 	}
 
+	if pages.Data == nil {
+		pages.Data = pages.f.wfs.bufPool.Get().([]byte)
+		atomic.AddInt32(&counter, 1)
+		glog.V(3).Infof("%s/%s acquire resource", pages.f.dir.Path, pages.f.Name, counter)
+	}
+
 	if offset < pages.Offset || offset >= pages.Offset+int64(len(pages.Data)) ||
 		pages.Offset+int64(len(pages.Data)) < offset+int64(len(data)) {
 		// if the data is out of range,