diff --git a/cmd/pd-server/main.go b/cmd/pd-server/main.go
index ab3cfdbb383..39b1119222f 100644
--- a/cmd/pd-server/main.go
+++ b/cmd/pd-server/main.go
@@ -132,7 +132,7 @@ func addFlags(cmd *cobra.Command) {
 	cmd.Flags().StringP("initial-cluster", "", "", "initial cluster configuration for bootstrapping, e,g. pd=http://127.0.0.1:2380")
 	cmd.Flags().StringP("join", "", "", "join to an existing cluster (usage: cluster's '${advertise-client-urls}'")
 	cmd.Flags().StringP("metrics-addr", "", "", "prometheus pushgateway address, leaves it empty will disable prometheus push")
-	cmd.Flags().StringP("log-level", "L", "info", "log level: debug, info, warn, error, fatal (default 'info')")
+	cmd.Flags().StringP("log-level", "L", "", "log level: debug, info, warn, error, fatal (default 'info')")
 	cmd.Flags().StringP("log-file", "", "", "log file path")
 	cmd.Flags().StringP("cacert", "", "", "path of file that contains list of trusted TLS CAs")
 	cmd.Flags().StringP("cert", "", "", "path of file that contains X509 certificate in PEM format")
diff --git a/pkg/mcs/resource_manager/server/config.go b/pkg/mcs/resource_manager/server/config.go
index 2c45ce5c355..4db55c96e4e 100644
--- a/pkg/mcs/resource_manager/server/config.go
+++ b/pkg/mcs/resource_manager/server/config.go
@@ -230,10 +230,6 @@ func (c *Config) Adjust(meta *toml.MetaData) error {
 	c.adjustLog(configMetaData.Child("log"))
 	c.Security.Encryption.Adjust()
 
-	if len(c.Log.Format) == 0 {
-		c.Log.Format = utils.DefaultLogFormat
-	}
-
 	c.Controller.Adjust(configMetaData.Child("controller"))
 	configutil.AdjustInt64(&c.LeaderLease, utils.DefaultLeaderLease)
 
@@ -244,6 +240,8 @@ func (c *Config) adjustLog(meta *configutil.ConfigMetaData) {
 	if !meta.IsDefined("disable-error-verbose") {
 		c.Log.DisableErrorVerbose = utils.DefaultDisableErrorVerbose
 	}
+	configutil.AdjustString(&c.Log.Format, utils.DefaultLogFormat)
+	configutil.AdjustString(&c.Log.Level, utils.DefaultLogLevel)
 }
 
 // GetTLSConfig returns the TLS config.
diff --git a/pkg/mcs/tso/server/config.go b/pkg/mcs/tso/server/config.go
index aedb7ebc1c0..ab9ca4aa9d0 100644
--- a/pkg/mcs/tso/server/config.go
+++ b/pkg/mcs/tso/server/config.go
@@ -226,10 +226,6 @@ func (c *Config) Adjust(meta *toml.MetaData, reloading bool) error {
 	c.adjustLog(configMetaData.Child("log"))
 	c.Security.Encryption.Adjust()
 
-	if len(c.Log.Format) == 0 {
-		c.Log.Format = utils.DefaultLogFormat
-	}
-
 	return nil
 }
 
@@ -237,6 +233,8 @@ func (c *Config) adjustLog(meta *configutil.ConfigMetaData) {
 	if !meta.IsDefined("disable-error-verbose") {
 		c.Log.DisableErrorVerbose = utils.DefaultDisableErrorVerbose
 	}
+	configutil.AdjustString(&c.Log.Format, utils.DefaultLogFormat)
+	configutil.AdjustString(&c.Log.Level, utils.DefaultLogLevel)
 }
 
 // Validate is used to validate if some configurations are right.
diff --git a/pkg/mcs/utils/constant.go b/pkg/mcs/utils/constant.go
index aa81425bc9f..c85c5d43e51 100644
--- a/pkg/mcs/utils/constant.go
+++ b/pkg/mcs/utils/constant.go
@@ -28,6 +28,8 @@ const (
 	DefaultHTTPGracefulShutdownTimeout = 5 * time.Second
 	// DefaultLogFormat is the default log format
 	DefaultLogFormat = "text"
+	// DefaultLogLevel is the default log level
+	DefaultLogLevel = "info"
 	// DefaultDisableErrorVerbose is the default value of DisableErrorVerbose
 	DefaultDisableErrorVerbose = true
 	// DefaultLeaderLease is the default value of LeaderLease
diff --git a/server/config/config.go b/server/config/config.go
index e7589dfd3f0..9f90d028b56 100644
--- a/server/config/config.go
+++ b/server/config/config.go
@@ -224,6 +224,7 @@ const (
 	minTSOUpdatePhysicalInterval     = 1 * time.Millisecond
 
 	defaultLogFormat = "text"
+	defaultLogLevel  = "info"
 
 	defaultMaxMovableHotPeerSize = int64(512)
 
@@ -497,10 +498,6 @@ func (c *Config) Adjust(meta *toml.MetaData, reloading bool) error {
 
 	c.Security.Encryption.Adjust()
 
-	if len(c.Log.Format) == 0 {
-		c.Log.Format = defaultLogFormat
-	}
-
 	c.Controller.Adjust(configMetaData.Child("controller"))
 
 	return nil
@@ -510,6 +507,8 @@ func (c *Config) adjustLog(meta *configutil.ConfigMetaData) {
 	if !meta.IsDefined("disable-error-verbose") {
 		c.Log.DisableErrorVerbose = defaultDisableErrorVerbose
 	}
+	configutil.AdjustString(&c.Log.Format, defaultLogFormat)
+	configutil.AdjustString(&c.Log.Level, defaultLogLevel)
 }
 
 // Clone returns a cloned configuration.
diff --git a/server/config/config_test.go b/server/config/config_test.go
index b8025a396b8..f77038ad4af 100644
--- a/server/config/config_test.go
+++ b/server/config/config_test.go
@@ -244,6 +244,22 @@ tso-update-physical-interval = "15s"
 	re.NoError(err)
 
 	re.Equal(maxTSOUpdatePhysicalInterval, cfg.TSOUpdatePhysicalInterval.Duration)
+
+	cfgData = `
+[log]
+level = "debug"
+`
+	flagSet = pflag.NewFlagSet("testlog", pflag.ContinueOnError)
+	flagSet.StringP("log-level", "L", "info", "log level: debug, info, warn, error, fatal (default 'info')")
+	flagSet.Parse(nil)
+	cfg = NewConfig()
+	err = cfg.Parse(flagSet)
+	re.NoError(err)
+	meta, err = toml.Decode(cfgData, &cfg)
+	re.NoError(err)
+	err = cfg.Adjust(&meta, false)
+	re.NoError(err)
+	re.Equal("debug", cfg.Log.Level)
 }
 
 func TestMigrateFlags(t *testing.T) {