I accompanied many z/VSE migrations to new releases or new hardware over the last years. In some cases we were involved after the migration, because the system didn't meet the expectations. In nearly all of those cases performance data of the system prior to the migration was not available, such as CPU utilization or I/O rates.
Therefore I recommend to measure the resource consumption (CPU utilization, I/O rates, ...) regularly, Not just, if you plan a migration, but also to detect e.g. resource shortages, growing workloads and for... [More]