Every Power11 consolidation strategy runs through PowerVM. Understanding how it works, and how VIOS fits into it, is essential before sizing a shared Power11 system across multiple workloads.
What PowerVM does
PowerVM is IBM's virtualization layer for Power Systems. It divides a physical Power11 server into multiple logical partitions (LPARs), each running its own instance of IBM i, AIX, or Linux, with dedicated or shared processor and memory resources allocated per partition. This is what allows a single Power11 system to replace several older, smaller machines.
Where VIOS fits in
The Virtual I/O Server (VIOS) is a specialized partition that owns the physical storage and network adapters and shares them virtually with the other logical partitions. Instead of every partition needing its own dedicated physical adapters, VIOS centralizes and virtualizes that access, which simplifies hardware requirements and cabling.
Why this matters for migration planning
If you are consolidating multiple AS400, Power9, or Power10 systems onto a single Power11 machine, your PowerVM and VIOS configuration is one of the most important design decisions in the project. Get it wrong and you can create I/O bottlenecks or single points of failure; get it right and you gain flexibility to resize partitions as workloads change.
Dual VIOS for resilience
Many production Power11 environments run two VIOS partitions in a redundant configuration, so that a VIOS update or failure does not take down I/O access for the partitions depending on it. This is a standard resilience pattern worth planning for during initial sizing, not adding after the fact.