diff --git a/src/api2/admin/datastore/backup.rs b/src/api2/admin/datastore/backup.rs
index e0f5055e..fc3df43a 100644
--- a/src/api2/admin/datastore/backup.rs
+++ b/src/api2/admin/datastore/backup.rs
@@ -33,7 +33,7 @@ pub fn api_method_upgrade_backup() -> ApiAsyncMethod {
         ObjectSchema::new("Upgraded to backup protocol.")
             .required("store", StringSchema::new("Datastore name."))
             .required("backup-type", StringSchema::new("Backup type.")
-                      .format(Arc::new(ApiStringFormat::Enum(vec!["vm".into(), "ct".into(), "host".into()]))))
+                      .format(Arc::new(ApiStringFormat::Enum(&["vm", "ct", "host"]))))
             .required("backup-id", StringSchema::new("Backup ID."))
     )
 }
diff --git a/src/api2/admin/datastore/pxar.rs b/src/api2/admin/datastore/pxar.rs
index d1162e47..d7cf821c 100644
--- a/src/api2/admin/datastore/pxar.rs
+++ b/src/api2/admin/datastore/pxar.rs
@@ -130,7 +130,7 @@ pub fn api_method_upload_pxar() -> ApiAsyncMethod {
             .required("store", StringSchema::new("Datastore name."))
             .required("archive-name", StringSchema::new("Backup archive name."))
             .required("backup-type", StringSchema::new("Backup type.")
-                      .format(Arc::new(ApiStringFormat::Enum(vec!["ct".into(), "host".into()]))))
+                      .format(Arc::new(ApiStringFormat::Enum(&["ct", "host"]))))
             .required("backup-id", StringSchema::new("Backup ID."))
             .required("backup-time", IntegerSchema::new("Backup time (Unix epoch.)")
                       .minimum(1547797308))
@@ -194,7 +194,7 @@ pub fn api_method_download_pxar() -> ApiAsyncMethod {
             .required("store", StringSchema::new("Datastore name."))
             .required("archive-name", StringSchema::new("Backup archive name."))
             .required("backup-type", StringSchema::new("Backup type.")
-                      .format(Arc::new(ApiStringFormat::Enum(vec!["ct".into(), "host".into()]))))
+                      .format(Arc::new(ApiStringFormat::Enum(&["ct", "host"]))))
             .required("backup-id", StringSchema::new("Backup ID."))
             .required("backup-time", IntegerSchema::new("Backup time (Unix epoch.)")
                       .minimum(1547797308))
diff --git a/src/api_schema/schema.rs b/src/api_schema/schema.rs
index 0223860b..3d8a3347 100644
--- a/src/api_schema/schema.rs
+++ b/src/api_schema/schema.rs
@@ -372,7 +372,7 @@ impl From<ArraySchema> for Arc<Schema> {
 }
 
 pub enum ApiStringFormat {
-    Enum(Vec<String>),
+    Enum(&'static [&'static str]),
     Pattern(&'static Regex),
     Complex(Arc<Schema>),
     VerifyFn(fn(&str) -> Result<(), Error>),
@@ -744,7 +744,7 @@ fn test_query_string() {
     let schema = ObjectSchema::new("Parameters.")
         .required(
             "name", StringSchema::new("Name.")
-                .format(Arc::new(ApiStringFormat::Enum(vec!["ev1".into(), "ev2".into()])))
+                .format(Arc::new(ApiStringFormat::Enum(&["ev1", "ev2"])))
         );
 
     let res = parse_query_string("name=noenum", &schema, true);
@@ -873,7 +873,7 @@ fn test_verify_function() {
 fn test_verify_complex_object() {
 
     let nic_models = Arc::new(ApiStringFormat::Enum(
-        vec!["e1000".into(), "virtio".into()]));
+        &["e1000", "virtio"]));
 
     let param_schema: Arc<Schema> = ObjectSchema::new("Properties.")
         .default_key("model")
diff --git a/src/cli/command.rs b/src/cli/command.rs
index 25a53f34..57c8fa8e 100644
--- a/src/cli/command.rs
+++ b/src/cli/command.rs
@@ -409,7 +409,7 @@ fn print_property_completion(
     }
 
     if let Schema::String(StringSchema { format: Some(format),  ..} ) = schema {
-        if let ApiStringFormat::Enum(list) = format.as_ref() {
+        if let ApiStringFormat::Enum(list) = *format.as_ref() {
             for value in list {
                 if value.starts_with(arg) {
                     println!("{}", value);