Migrating a Resource to a Different Version

An existing resource takes on the new resource type version when the system administrator edits the Type_version property of the resource. This follows the same conventions that are used to edit other resource properties, except that some information will be derived or taken from the new resource type version instead of the current version:

• Resource property attributes for all properties such as min, max, arraymin, arraymax, default, and tunability are taken from the new resource type version

• The tunability applicable to the Type_version property is taken from the #$upgrade_from directives in the RTR file and the RT_version property of the resource type of the existing resource. This tunability is unlike the tunability described in property_attributes(5).

• The Validate method for the new resource type version will be applied. This ensures that the property attributes are valid for the new resource type. If the existing resource property attributes do not satisfy the validation conditions of the new resource type version, the system administrator has to provide valid values for such properties on the scrgadm command line. This can occur if the newer resource type version starts to use a property that was not declared in the earlier version and which does not have a default. It might also occur if the existing resource already has a property which was assigned a value that is invalid for the newer resource type version.

• Resource properties that were declared in an older version of the resource type can be undeclared in the newer version. When the resource is migrated to the newer version, the property will be deleted from the resource.

The Validate method can query the current Type_version of the resource (using scha_resource_get) as well as the new Type_version (which is passed on the Validate command line). Therefore, Validate can rule out upgrades from unsupported versions.