diff --git a/types/types.go b/types/types.go
index 80f9255169..7d4ceca8e3 100644
--- a/types/types.go
+++ b/types/types.go
@@ -220,6 +220,7 @@ const (
 
 	BackupStoreTypeS3     = "s3"
 	BackupStoreTypeCIFS   = "cifs"
+	BackupStoreTypeNFS    = "nfs"
 	BackupStoreTypeAZBlob = "azblob"
 
 	AWSIAMRoleAnnotation = "iam.amazonaws.com/role"
diff --git a/webhook/resources/backuptarget/validator.go b/webhook/resources/backuptarget/validator.go
new file mode 100644
index 0000000000..9b70da4149
--- /dev/null
+++ b/webhook/resources/backuptarget/validator.go
@@ -0,0 +1,244 @@
+package backuptarget
+
+import (
+	"fmt"
+	"net/url"
+	"regexp"
+	"strings"
+
+	"github.com/pkg/errors"
+
+	admissionregv1 "k8s.io/api/admissionregistration/v1"
+
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/sets"
+
+	"github.com/longhorn/longhorn-manager/datastore"
+	"github.com/longhorn/longhorn-manager/types"
+	"github.com/longhorn/longhorn-manager/util"
+	"github.com/longhorn/longhorn-manager/webhook/admission"
+
+	longhorn "github.com/longhorn/longhorn-manager/k8s/pkg/apis/longhorn/v1beta2"
+	werror "github.com/longhorn/longhorn-manager/webhook/error"
+)
+
+type backupTargetURLType string
+
+const (
+	backupTargetURLTypeBucket  = backupTargetURLType("bucket")
+	backupTargetURLTypeOptions = backupTargetURLType("options")
+)
+
+type backupTargetValidator struct {
+	admission.DefaultValidator
+	ds *datastore.DataStore
+}
+
+func NewValidator(ds *datastore.DataStore) admission.Validator {
+	return &backupTargetValidator{ds: ds}
+}
+
+func (b *backupTargetValidator) Resource() admission.Resource {
+	return admission.Resource{
+		Name:       "backuptargets",
+		Scope:      admissionregv1.NamespacedScope,
+		APIGroup:   longhorn.SchemeGroupVersion.Group,
+		APIVersion: longhorn.SchemeGroupVersion.Version,
+		ObjectType: &longhorn.BackupTarget{},
+		OperationTypes: []admissionregv1.OperationType{
+			admissionregv1.Create,
+			admissionregv1.Update,
+		},
+	}
+}
+
+func (b *backupTargetValidator) Create(request *admission.Request, newObj runtime.Object) error {
+	backupTarget := newObj.(*longhorn.BackupTarget)
+
+	if !util.ValidateName(backupTarget.Name) {
+		return werror.NewInvalidError(fmt.Sprintf("invalid name %v", backupTarget.Name), "")
+	}
+
+	if err := b.validateBackupTargetURL(backupTarget.Spec.BackupTargetURL); err != nil {
+		return werror.NewInvalidError(err.Error(), "")
+	}
+
+	if err := b.validateCredentialSecret(backupTarget.Spec.CredentialSecret); err != nil {
+		return werror.NewInvalidError(err.Error(), "")
+	}
+
+	return nil
+}
+
+func (b *backupTargetValidator) Update(request *admission.Request, oldObj runtime.Object, newObj runtime.Object) error {
+	oldBackupTarget := oldObj.(*longhorn.BackupTarget)
+	newBackupTarget := newObj.(*longhorn.BackupTarget)
+
+	urlChanged := oldBackupTarget.Spec.BackupTargetURL != newBackupTarget.Spec.BackupTargetURL
+	secretChanged := oldBackupTarget.Spec.CredentialSecret != newBackupTarget.Spec.CredentialSecret
+
+	if urlChanged || secretChanged {
+		if err := b.validateDRVolume(newBackupTarget); err != nil {
+			return werror.NewInvalidError(err.Error(), "")
+		}
+	}
+
+	if urlChanged {
+		if err := b.validateBackupTargetURL(newBackupTarget.Spec.BackupTargetURL); err != nil {
+			return werror.NewInvalidError(err.Error(), "")
+		}
+	}
+
+	if secretChanged {
+		if err := b.validateCredentialSecret(newBackupTarget.Spec.CredentialSecret); err != nil {
+			return werror.NewInvalidError(err.Error(), "")
+		}
+	}
+
+	return nil
+}
+
+func (b *backupTargetValidator) validateBackupTargetURL(backupTargetURL string) error {
+	if backupTargetURL == "" {
+		return nil
+	}
+
+	u, err := url.Parse(backupTargetURL)
+	if err != nil {
+		return errors.Wrapf(err, "failed to parse %v as url", backupTargetURL)
+	}
+
+	if err := checkBackupTargetURLFormat(u); err != nil {
+		return err
+	}
+
+	if err := b.checkBackupTargetURLExisting(u); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func checkBackupTargetURLFormat(u *url.URL) error {
+	// Check whether have $ or , have been set in BackupTarget path
+	regStr := `[\$\,]`
+	if u.Scheme == "cifs" {
+		// The $ in SMB/CIFS URIs means that the share is hidden.
+		regStr = `[\,]`
+	}
+
+	reg := regexp.MustCompile(regStr)
+	findStr := reg.FindAllString(u.Path, -1)
+	if len(findStr) != 0 {
+		return fmt.Errorf("url %s, contains %v", u.String(), strings.Join(findStr, " or "))
+	}
+	return nil
+}
+
+func (b *backupTargetValidator) checkBackupTargetURLExisting(u *url.URL) error {
+	var btURLType backupTargetURLType
+	var creatingBackupTargetPath string
+
+	switch u.Scheme {
+	case types.BackupStoreTypeAZBlob, types.BackupStoreTypeS3:
+		btURLType = backupTargetURLTypeBucket
+		creatingBackupTargetPath = u.String()
+	case types.BackupStoreTypeCIFS, types.BackupStoreTypeNFS:
+		btURLType = backupTargetURLTypeOptions
+		creatingBackupTargetPath = strings.TrimRight(u.Host+u.Path, "/")
+	default:
+		return fmt.Errorf("url %s with the unsupported protocol %v", u.String(), u.Scheme)
+	}
+
+	bts, err := b.ds.ListBackupTargetsRO()
+	if err != nil {
+		return err
+	}
+	for _, bt := range bts {
+		uExisting, err := url.Parse(bt.Spec.BackupTargetURL)
+		if err != nil {
+			return errors.Wrapf(err, "failed to parse %v as url", bt.Spec.BackupTargetURL)
+		}
+		if uExisting.Scheme != u.Scheme {
+			continue
+		}
+		var backupTargetPath string
+		if btURLType == backupTargetURLTypeBucket {
+			backupTargetPath = uExisting.String()
+		}
+		if btURLType == backupTargetURLTypeOptions {
+			backupTargetPath = strings.TrimRight(uExisting.Host+uExisting.Path, "/")
+		}
+		if backupTargetPath == creatingBackupTargetPath {
+			return fmt.Errorf("url %s is the same to backup target %v", u.String(), bt.Name)
+		}
+	}
+
+	return nil
+}
+
+func (b *backupTargetValidator) validateCredentialSecret(secretName string) error {
+	namespace, err := b.ds.GetLonghornNamespace()
+	if err != nil {
+		return errors.Wrapf(err, "failed to get Longhorn namespace")
+	}
+	secret, err := b.ds.GetSecretRO(namespace.Name, secretName)
+	if err != nil {
+		if !apierrors.IsNotFound(err) {
+			return errors.Wrapf(err, "failed to get the secret before modifying backup target credential secret")
+		}
+		return nil
+	}
+	checkKeyList := []string{
+		types.AWSAccessKey,
+		types.AWSIAMRoleAnnotation,
+		types.AWSIAMRoleArn,
+		types.AWSAccessKey,
+		types.AWSSecretKey,
+		types.AWSEndPoint,
+		types.AWSCert,
+		types.CIFSUsername,
+		types.CIFSPassword,
+		types.AZBlobAccountName,
+		types.AZBlobAccountKey,
+		types.AZBlobEndpoint,
+		types.AZBlobCert,
+		types.HTTPSProxy,
+		types.HTTPProxy,
+		types.NOProxy,
+		types.VirtualHostedStyle,
+	}
+	for _, checkKey := range checkKeyList {
+		if value, ok := secret.Data[checkKey]; ok {
+			if strings.TrimSpace(string(value)) != string(value) {
+				return fmt.Errorf("there is space or new line in %s", checkKey)
+			}
+		}
+	}
+	return nil
+}
+
+func (b *backupTargetValidator) validateDRVolume(backupTarget *longhorn.BackupTarget) error {
+	vs, err := b.ds.ListDRVolumesRO()
+	if err != nil {
+		return errors.Wrapf(err, "failed to list standby volume when modifying BackupTarget")
+	}
+
+	backupTargetURL := backupTarget.Spec.BackupTargetURL
+	if len(vs) != 0 {
+		standbyVolumeNames := sets.NewString()
+		for k, v := range vs {
+			specCharIndex := strings.Index(v.Spec.FromBackup, "?")
+			fromBackupURL := v.Spec.FromBackup[:specCharIndex]
+			fromBackupTargetName, isFound := v.Labels[types.LonghornLabelBackupTarget]
+			if (isFound && fromBackupTargetName == backupTarget.Name) || fromBackupURL == backupTargetURL {
+				standbyVolumeNames.Insert(k)
+			}
+		}
+		if standbyVolumeNames.Len() != 0 {
+			return fmt.Errorf("cannot modify BackupTarget since there are existing standby volumes: %v", standbyVolumeNames)
+		}
+	}
+	return nil
+}
diff --git a/webhook/server/validation.go b/webhook/server/validation.go
index a48a52ef5d..92c175d350 100644
--- a/webhook/server/validation.go
+++ b/webhook/server/validation.go
@@ -11,6 +11,7 @@ import (
 	"github.com/longhorn/longhorn-manager/webhook/admission"
 	"github.com/longhorn/longhorn-manager/webhook/resources/backingimage"
 	"github.com/longhorn/longhorn-manager/webhook/resources/backup"
+	"github.com/longhorn/longhorn-manager/webhook/resources/backuptarget"
 	"github.com/longhorn/longhorn-manager/webhook/resources/engine"
 	"github.com/longhorn/longhorn-manager/webhook/resources/node"
 	"github.com/longhorn/longhorn-manager/webhook/resources/orphan"
@@ -38,6 +39,7 @@ func Validation(ds *datastore.DataStore) (http.Handler, []admission.Resource, er
 		recurringjob.NewValidator(ds),
 		backingimage.NewValidator(ds),
 		backup.NewValidator(ds),
+		backuptarget.NewValidator(ds),
 		volume.NewValidator(ds, currentNodeID),
 		orphan.NewValidator(ds),
 		snapshot.NewValidator(ds),