You develop a skip-level (or multi-hop) upgrade to update your Production environment to a version of the Identity Manager product that is beyond the next major release from your current version. For example, if you are currently using Version 6.0 of Identity Manager and want to upgrade directly to Version 8.1, this upgrade path would require a skip-level upgrade.
Upgrading several versions normally requires a series of upgrades. However, many customers want to minimize the number of upgrades in the Production environment, which in turn minimizes the downtime of your Identity Manager application, minimizes the cost of retesting the Identity Manager application, and minimizes the cost of retraining the people using the Identity Manager application.
Developing a single upgrade procedure to update a target Identity Manager version is technically possible and some customers find it feasible. The key point to understand is that, even though you are performing a skip-level upgrade in your Production environment, you still must perform each hop in your Development environment. For example, you must upgrade Identity Manager from Version 7.0 to Version 7.1 to Version 7.1.1 to Version 8.0 to Version 8.1 in your Development environment. After each hop, you build up a set of artifacts that is cumulative.
The most common approach for a skip-level upgrade is to update your application baseline with configurations and customizations that have been updated to work with each Identity Manager version on the path to your target version of Identity Manager. Your baseline also includes a cumulative script to update databases and a cumulative subset of update.xml. The net effect is that you develop a single upgrade procedure that makes changes that are equivalent to the changes that performing the series of upgrades would have done.
Performing a skip-level upgrade is more complex than a standard or single-hop upgrade. Skip-level upgrades require more technical insight into the mechanisms used by the Identity Manager product upgrade. A skip-level upgrade also requires closer analysis of the upgrade content for each Identity Manager product version in the upgrade path. Closer analysis allows you to produce artifacts that are properly cumulative and yet minimal. For example, if you simply combine all of the database table upgrade scripts into one script or if you combine the subsets of update.xml from each step into one subset, then your upgrade might perform a great deal of redundant processing.
This chapter describes special considerations for a skip-level upgrade. If you are uncertain how to proceed or if these considerations seem unclear to you, contact Sun Professional Services to request assistance with planning your upgrade.