Glossary Term

VIOS (Virtual I/O Server)

IBM PowerVM's virtualization partition that shares physical I/O adapters, including Fibre Channel storage connections, across multiple client partitions on a Power server.

Definition

VIOS (Virtual I/O Server) is a specialized PowerVM partition that owns physical I/O adapters directly and presents virtualized access to those adapters to other partitions on the same Power server, including IBM i, AIX, and Linux client partitions. For FlashSystem storage attachment specifically, VIOS combined with NPIV lets a physical Fibre Channel adapter be shared across multiple client partitions rather than requiring a dedicated adapter per partition.

Whether VIOS is required for a given FlashSystem attachment depends on the Power server, IBM i release, and partition design. Some configurations support native direct or SAN attach without a VIOS layer at all.

Example

An IBM i shop consolidating several partitions' storage attachment onto shared Fibre Channel adapters would use VIOS with NPIV rather than dedicating a physical adapter to each partition.