Depending on the migration plan you developed, you may want to meet or exceed the performance you get with your current system. For example, you might decide to apply guidelines like these:
For parallel with replication:
Be sure to measure the overhead of the replication mechanism. For example, if the replication costs 10%, do not begin parallel operations until release 12.5 is tuned to outperform by 10%.
For an around-the-clock operation, you may decide that an initial goal of breaking even is reasonable.
For cutover without replication, gear the migration for equivalent performance between the old and new systems. A goal of breaking even the first week is reasonable.
A phased cutover is subject to the highest performance expectations. Some performance tuning of the production workload after cutover of the production server may be best. You can time the production server cutover to occur as soon as performance gains are acceptable and testing is successful.
See Chapter 4, “Plan: Writing a Plan and Getting Ready to Migrate” for information on migration methods.