System administrators require the ability to install and register a new version of an existing resource type, to allow the registration of multiple versions of a given resource type, and to migrate an existing resource to a new version of the resource type without having to delete and recreate the resource. Resource developers need to understand the requirements for providing resource type upgrade and resource migration.
A new version of a resource type can differ from a previous version in several ways:
Attributes of resource type properties may change
The set of declared resource properties, including standard and extension properties, may change
The set of declared methods may differ
The implementation of methods or monitors may change.
The resource type developer decides when an existing resource can be migrated to a new version from among the following tunability options. The options are listed from least restrictive to most restrictive:
Throughout this chapter, the scrgadm command is used when discussing how to do an upgrade. The administrator is not restricted to using the scrgadm command but can also use the GUI or the scsetup command to do the upgrade.