Answer
Gather the evidence that describes workload behavior, not only the current machine label.
- Partition-level processor use
- Memory allocation and pressure
- Disk busy
- I/O latency
- Storage layout
- Backup window
- Network and adapter needs
- HMC level
- Firmware
- Operating system releases
- Named peak events such as month-end or inventory close
The useful goal is to separate current average demand, current peak demand, and expected growth. That lets the quote solve the workload instead of only replacing the current model with a newer label.