diff --git a/etcdserver/server.go b/etcdserver/server.go
index e34fafbdd5f..23e719ccf96 100644
--- a/etcdserver/server.go
+++ b/etcdserver/server.go
@@ -765,7 +765,10 @@ func (s *EtcdServer) applyAll(ep *etcdProgress, apply *apply) {
 }
 
 func (s *EtcdServer) applySnapshot(ep *etcdProgress, apply *apply) {
+	plog.Info("start applySnapshot")
+
 	if raft.IsEmptySnap(apply.snapshot) {
+		plog.Info("start applySnapshot raft.IsEmptySnap() returns true. exit")
 		return
 	}
 
@@ -863,6 +866,7 @@ func (s *EtcdServer) applySnapshot(ep *etcdProgress, apply *apply) {
 	ep.appliedi = apply.snapshot.Metadata.Index
 	ep.snapi = ep.appliedi
 	ep.confState = apply.snapshot.Metadata.ConfState
+	plog.Info("applySnapshot done")
 }
 
 func (s *EtcdServer) applyEntries(ep *etcdProgress, apply *apply) {
diff --git a/pkg/netutil/isolate_linux.go b/pkg/netutil/isolate_linux.go
index c0128a5a50b..845a74085ca 100644
--- a/pkg/netutil/isolate_linux.go
+++ b/pkg/netutil/isolate_linux.go
@@ -43,7 +43,9 @@ func RecoverPort(port int) error {
 
 // SetLatency adds latency in millisecond scale with random variations.
 func SetLatency(ms, rv int) error {
+	fmt.Printf("SetLatency ms %v rv %v\n", ms, rv)
 	ifce, err := GetDefaultInterface()
+	fmt.Printf("SetLatency GetDefaultInterface() status: ifce %v, err (%v)\n", ifce, err)
 	if err != nil {
 		return err
 	}
@@ -52,24 +54,37 @@ func SetLatency(ms, rv int) error {
 		rv = 1
 	}
 	cmdStr := fmt.Sprintf("sudo tc qdisc add dev %s root netem delay %dms %dms distribution normal", ifce, ms, rv)
+	fmt.Printf("SetLatency cmd: %v\n", cmdStr)
 	_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
 	if err != nil {
+		fmt.Printf("SetLatency cmd: %v error (%v)\n", cmdStr, err)
 		// the rule has already been added. Overwrite it.
 		cmdStr = fmt.Sprintf("sudo tc qdisc change dev %s root netem delay %dms %dms distribution normal", ifce, ms, rv)
+		fmt.Printf("SetLatency cmd: %v\n", cmdStr)
 		_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
 		if err != nil {
+			fmt.Printf("SetLatency cmd: %v error (%v)\n", cmdStr, err)
 			return err
 		}
 	}
+	fmt.Printf("SetLatency ms %v rv %v done\n", ms, rv)
+
 	return nil
 }
 
 // RemoveLatency resets latency configurations.
 func RemoveLatency() error {
+	fmt.Printf("RemoveLatency\n")
 	ifce, err := GetDefaultInterface()
+	fmt.Printf("RemoveLatency GetDefaultInterface() status: ifce %v, err (%v)\n", ifce, err)
 	if err != nil {
 		return err
 	}
-	_, err = exec.Command("/bin/sh", "-c", fmt.Sprintf("sudo tc qdisc del dev %s root netem", ifce)).Output()
+	cmdStr := fmt.Sprintf("sudo tc qdisc del dev %s root netem", ifce)
+	fmt.Printf("RemoveLatency cmd: %v\n", cmdStr)
+	_, err = exec.Command("/bin/sh", "-c", cmdStr).Output()
+	if err != nil {
+		fmt.Printf("RemoveLatency cmd: %v\n error (%v)\n", cmdStr, err)
+	}
 	return err
 }
diff --git a/raft/raft.go b/raft/raft.go
index 288989d16c3..51b373f5c90 100644
--- a/raft/raft.go
+++ b/raft/raft.go
@@ -1102,10 +1102,14 @@ func (r *raft) handleSnapshot(m pb.Message) {
 		r.logger.Infof("%x [commit: %d] restored snapshot [index: %d, term: %d]",
 			r.id, r.raftLog.committed, sindex, sterm)
 		r.send(pb.Message{To: m.From, Type: pb.MsgAppResp, Index: r.raftLog.lastIndex()})
+		r.logger.Infof("%x [commit: %d] restored snapshot [index: %d, term: %d] sent MsgApp",
+			r.id, r.raftLog.committed, sindex, sterm)
 	} else {
 		r.logger.Infof("%x [commit: %d] ignored snapshot [index: %d, term: %d]",
 			r.id, r.raftLog.committed, sindex, sterm)
 		r.send(pb.Message{To: m.From, Type: pb.MsgAppResp, Index: r.raftLog.committed})
+		r.logger.Infof("%x [commit: %d] ignored snapshot [index: %d, term: %d] sent MsgApp",
+			r.id, r.raftLog.committed, sindex, sterm)
 	}
 }
 
diff --git a/tools/functional-tester/etcd-tester/checks.go b/tools/functional-tester/etcd-tester/checks.go
index a648d53bffb..e919b4eef93 100644
--- a/tools/functional-tester/etcd-tester/checks.go
+++ b/tools/functional-tester/etcd-tester/checks.go
@@ -80,15 +80,15 @@ func (hc *hashChecker) Check() error {
 type leaseChecker struct{ ls *leaseStresser }
 
 func (lc *leaseChecker) Check() error {
-	plog.Infof("checking revoked leases %v", lc.ls.revokedLeases.leases)
+	plog.Debugf("checking revoked leases %v", lc.ls.revokedLeases.leases)
 	if err := lc.check(true, lc.ls.revokedLeases.leases); err != nil {
 		return err
 	}
-	plog.Infof("checking alive leases %v", lc.ls.aliveLeases.leases)
+	plog.Debugf("checking alive leases %v", lc.ls.aliveLeases.leases)
 	if err := lc.check(false, lc.ls.aliveLeases.leases); err != nil {
 		return err
 	}
-	plog.Infof("checking short lived leases %v", lc.ls.shortLivedLeases.leases)
+	plog.Debugf("checking short lived leases %v", lc.ls.shortLivedLeases.leases)
 	return lc.checkShortLivedLeases()
 
 }
@@ -122,14 +122,14 @@ func (lc *leaseChecker) checkShortLivedLease(ctx context.Context, leaseID int64)
 			return nil
 		}
 		if err != nil {
-			plog.Warningf("retry %d. failed to retrieve lease %v error (%v)", i, leaseID, err)
+			plog.Debugf("retry %d. failed to retrieve lease %v error (%v)", i, leaseID, err)
 			continue
 		}
 		if resp.TTL > 0 {
-			plog.Warningf("lease %v is not expired. sleep for %d until it expires.", leaseID, resp.TTL)
+			plog.Debugf("lease %v is not expired. sleep for %d until it expires.", leaseID, resp.TTL)
 			time.Sleep(time.Duration(resp.TTL) * time.Second)
 		} else {
-			plog.Warningf("retry %d. lease %v is expired but not yet revoked", i, leaseID)
+			plog.Debugf("retry %d. lease %v is expired but not yet revoked", i, leaseID)
 			time.Sleep(time.Second)
 		}
 		if err = lc.checkLease(ctx, false, leaseID); err != nil {
diff --git a/tools/functional-tester/etcd-tester/failure_agent.go b/tools/functional-tester/etcd-tester/failure_agent.go
index 5dddec5302f..d2545588822 100644
--- a/tools/functional-tester/etcd-tester/failure_agent.go
+++ b/tools/functional-tester/etcd-tester/failure_agent.go
@@ -98,18 +98,26 @@ func newFailureIsolateAll() failure {
 }
 
 func injectLatency(m *member) error {
+	plog.Printf("%v Injecting Latency", m.ClientURL)
 	if err := m.Agent.SetLatency(slowNetworkLatency, randomVariation); err != nil {
-		m.Agent.RemoveLatency()
+		plog.Printf("%v Injecting Latency error (%v)", m.ClientURL, err)
+		rErr := m.Agent.RemoveLatency()
+		plog.Printf("%v Injecting Latency's Removing Latency status %v", m.ClientURL, rErr)
 		return err
 	}
+	plog.Printf("%v Injecting Latency done", m.ClientURL)
 	return nil
 }
 
 func recoverLatency(m *member) error {
+	plog.Printf("%v recovering Latency", m.ClientURL)
 	if err := m.Agent.RemoveLatency(); err != nil {
+		plog.Printf("%v recovering Latency error (%v)", m.ClientURL, err)
 		return err
 	}
+	plog.Printf("%v recovering Latency sleep for %v", m.ClientURL, waitRecover)
 	time.Sleep(waitRecover)
+	plog.Printf("%v recovering Latency done", m.ClientURL)
 	return nil
 }
 
diff --git a/tools/functional-tester/etcd-tester/main.go b/tools/functional-tester/etcd-tester/main.go
index 18ecfcb53f1..b2441e3a3f8 100644
--- a/tools/functional-tester/etcd-tester/main.go
+++ b/tools/functional-tester/etcd-tester/main.go
@@ -167,16 +167,23 @@ func makeFailures(types string, c *cluster) []failure {
 		switch fails[i] {
 		case "default":
 			defaultFailures := []failure{
-				newFailureKillAll(),
-				newFailureKillMajority(),
-				newFailureKillOne(),
-				newFailureKillLeader(),
-				newFailureKillOneForLongTime(),
-				newFailureKillLeaderForLongTime(),
-				newFailureIsolate(),
-				newFailureIsolateAll(),
-				newFailureSlowNetworkOneMember(),
-				newFailureSlowNetworkLeader(),
+				// newFailureKillAll(),
+				// newFailureKillMajority(),
+				// newFailureKillOne(),
+				// newFailureKillLeader(),
+				// newFailureKillOneForLongTime(),
+				// newFailureKillLeaderForLongTime(),
+				// newFailureIsolate(),
+				// newFailureIsolateAll(),
+				// newFailureSlowNetworkOneMember(),
+				// newFailureSlowNetworkLeader(),
+				newFailureSlowNetworkAll(),
+				newFailureSlowNetworkAll(),
+				newFailureSlowNetworkAll(),
+				newFailureSlowNetworkAll(),
+				newFailureSlowNetworkAll(),
+				newFailureSlowNetworkAll(),
+				newFailureSlowNetworkAll(),
 				newFailureSlowNetworkAll(),
 			}
 			failures = append(failures, defaultFailures...)