diff --git a/apis/archiver/v1alpha1/helpers.go b/apis/archiver/v1alpha1/helpers.go
index e097263e63..789e2e19bc 100644
--- a/apis/archiver/v1alpha1/helpers.go
+++ b/apis/archiver/v1alpha1/helpers.go
@@ -45,3 +45,13 @@ func (_ MariaDBArchiver) CustomResourceDefinition() *apiextensions.CustomResourc
 func (_ MSSQLServerArchiver) CustomResourceDefinition() *apiextensions.CustomResourceDefinition {
 	return crds.MustCustomResourceDefinition(SchemeGroupVersion.WithResource(ResourcePluralMSSQLServerArchiver))
 }
+
+func SetDefaultLogBackupOptions(log *LogBackupOptions) *LogBackupOptions {
+	if log == nil {
+		log = &LogBackupOptions{
+			SuccessfulLogHistoryLimit: 5,
+			FailedLogHistoryLimit:     5,
+		}
+	}
+	return log
+}
diff --git a/apis/kubedb/v1alpha2/mssqlserver_helpers.go b/apis/kubedb/v1alpha2/mssqlserver_helpers.go
index 16194974eb..9eb763a93d 100644
--- a/apis/kubedb/v1alpha2/mssqlserver_helpers.go
+++ b/apis/kubedb/v1alpha2/mssqlserver_helpers.go
@@ -343,6 +343,9 @@ func (m *MSSQLServer) SetDefaults() {
 			m.Spec.Replicas = pointer.Int32P(1)
 		}
 	} else if m.IsAvailabilityGroup() {
+		if m.Spec.Topology.AvailabilityGroup == nil {
+			m.Spec.Topology.AvailabilityGroup = &MSSQLServerAvailabilityGroupSpec{}
+		}
 		if m.Spec.Topology.AvailabilityGroup.LeaderElection == nil {
 			m.Spec.Topology.AvailabilityGroup.LeaderElection = &MSSQLServerLeaderElectionConfig{
 				// The upper limit of election timeout is 50000ms (50s), which should only be used when deploying a