Upgrading from an AS400 or iSeries system to IBM Power11 is one of the most significant infrastructure decisions an organization can make. This guide walks through the key phases of a successful migration...
Phase 1: Workload Assessment
Before selecting hardware, audit your current environment. Document processor utilization, memory usage, disk I/O patterns, and IBM i version. Use IBM's Performance Management tool (Collection Services) to capture baseline data over 30 days. Identify peak workloads, batch windows, and any applications that may require remediation before migration.
Phase 2: Hardware Selection
IBM Power11 offers scale-out (S-series) and enterprise (L/E-series) models. For most AS400 migration candidates, the Power11 S1122 or S1124 is the appropriate starting point. Your IBM Business Partner can help size the new system based on your collected performance data using IBM's capacity planning tools.
Phase 3: IBM i Version Planning
A hardware upgrade is the ideal time to advance your IBM i operating system version. If you are running IBM i 7.3 or earlier, plan to move to IBM i 7.5 (the current technology refresh). Verify that all third-party software and custom applications are compatible with the target IBM i version before proceeding.
Phase 4: Data Migration Strategy
IBM i migration options include BRMS save/restore (recommended for most organizations), GoSave/GoRestore, or virtual tape with VIOS. For large environments, consider a phased migration that moves non-critical workloads first to validate the new system before the primary cutover.
Phase 5: Cutover Planning
Define your cutover window, rollback plan, and success criteria. Most AS400 to Power11 migrations can be completed in a weekend maintenance window. Test your backup and restore procedures at least 60 days before the planned cutover date. Document all IP addresses, user profiles, and system values that need to be reconfigured on the new system.
Next Steps
Work with an IBM Business Partner who specializes in IBM i migrations. They can provide a detailed migration plan, system sizing, and hands-on migration support to minimize risk and downtime.