diff --git a/controller/node_controller.go b/controller/node_controller.go
index 6031c31653..167f0ff0c4 100644
--- a/controller/node_controller.go
+++ b/controller/node_controller.go
@@ -49,8 +49,12 @@ type NodeController struct {
 	sStoreSynced cache.InformerSynced
 
 	queue workqueue.RateLimitingInterface
+
+	getDiskInfoHandler GetDiskInfoHandler
 }
 
+type GetDiskInfoHandler func(string) (*util.DiskInfo, error)
+
 func NewNodeController(
 	ds *datastore.DataStore,
 	scheme *runtime.Scheme,
@@ -79,6 +83,8 @@ func NewNodeController(
 		sStoreSynced: settingInformer.Informer().HasSynced,
 
 		queue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "longhorn-node"),
+
+		getDiskInfoHandler: util.GetDiskInfo,
 	}
 
 	nodeInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
@@ -316,7 +322,7 @@ func (nc *NodeController) syncDiskStatus(node *longhorn.Node) error {
 			delete(replicaDiskMap, diskID)
 		}
 		// get disk available size
-		diskInfo, err := util.GetDiskInfo(disk.Path)
+		diskInfo, err := nc.getDiskInfoHandler(disk.Path)
 		if err != nil {
 			logrus.Errorf("Get disk information on node %v error: %v", node.Name, err)
 		} else {
diff --git a/controller/node_controller_test.go b/controller/node_controller_test.go
index 81eca3a376..29c50794c7 100644
--- a/controller/node_controller_test.go
+++ b/controller/node_controller_test.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/rancher/longhorn-manager/datastore"
 	"github.com/rancher/longhorn-manager/types"
+	"github.com/rancher/longhorn-manager/util"
 
 	longhorn "github.com/rancher/longhorn-manager/k8s/pkg/apis/longhorn/v1alpha1"
 	lhfake "github.com/rancher/longhorn-manager/k8s/pkg/client/clientset/versioned/fake"
@@ -52,6 +53,7 @@ func newTestNodeController(lhInformerFactory lhinformerfactory.SharedInformerFac
 	nc := NewNodeController(ds, scheme.Scheme, nodeInformer, settingInformer, podInformer, kubeClient, TestNamespace, controllerID)
 	fakeRecorder := record.NewFakeRecorder(100)
 	nc.eventRecorder = fakeRecorder
+	nc.getDiskInfoHandler = fakeGetDiskInfo
 
 	nc.nStoreSynced = alwaysReady
 	nc.pStoreSynced = alwaysReady
@@ -59,6 +61,20 @@ func newTestNodeController(lhInformerFactory lhinformerfactory.SharedInformerFac
 	return nc
 }
 
+func fakeGetDiskInfo(directory string) (*util.DiskInfo, error) {
+	return &util.DiskInfo{
+		Fsid:       "fsid",
+		Path:       directory,
+		Type:       "ext4",
+		FreeBlock:  0,
+		TotalBlock: 0,
+		BlockSize:  0,
+
+		StorageMaximum:   0,
+		StorageAvailable: 0,
+	}, nil
+}
+
 func (s *TestSuite) TestSyncNode(c *C) {
 	testCases := map[string]*NodeTestCase{}
 	MountPropagationBidirectional := v1.MountPropagationBidirectional