AIX Migration : Overview
Objective of this document is to describe the procedure to migrate AIX Servers hosted on an older IBM pSeries model (eg. P5) to a newer model (P8). The new server environment will be virtual (LPAR) and built over VIO (Virtual IO Server) managed with HMC (Hardware Management Console).
During the process, the OS will also be upgraded to a newer level, AIX 7.1. The newer models need a minimum OS level to support its architecture. The data will be migrated preserving the Volume and File Structure (LVM) together with Applications and user IDs. It is assumed that the respective owners will ensure that the Applications (and DB if any) is compatible and supported on the newer OS level.
The new server can be provisioned on a different subnet with new IPs and hostname. However, in extreme cases, if the requirement dictates that the same IP and hostname shall be retained for reasons such as the hostname, IPs or license are hardcoded in external Applications and interfaces. The procedure in this document is designed to retain the same IP and Hostname on cutover. A temporary IP and Hostname are used during the build and initial verification stage until the cutover such that there is a minimal outage. Under controlled circumstances, if the new server and configurations are verified, tested, the cutover including validation can be completed in about ten hours window. The Application and DB team are expected to be working in parallel with the system engineers for a seamless transition.
All necessary licenses and hardening, including the Network allocations such the Firewall rules, are assumed to be managed by the respective teams, besides the OS and backup manager on TSM, Netbackup or other standard infrastructure tools. Necessary vendor support for Application, DB and OS will have to be arranged up front.
The milestones during the overall workflow can be identified as:
- Rack Physical Server
- Rack HMC
- Route Network Cables
- Install HMC OS
- Upgrade HMC
- Build LPARs
- Build VIO Servers
- Build a NIM Server
- Backup Existing Server
- Build (Clone) New Server
- Copy Data (datavg)
- Validate, Test Integrity
- Sync Data
- Cutover, Place into Service
- Integration Support
It is recommended that a Proof Of Concept (POC) is performed before the actual implementation. In almost all cases, the systems migrated would have been operating for many years and the current owners would have minimum understanding of the configuration (firewall rules and applications are potential subjects). Sometimes many applications are also grown out of support. A POC will identify issues upfront and provide the platform to make necessary amendments and fine tuning of the procedure, design involved.
Once the Design and Architecture document is completed identifying the:
- Network IPs
- Ports (Switches)
- Host Names (DNS entries)
- Storage Size (SAN if involved)
- Firewall Rules, Licences
- User IDs
- CPU and Memory
the actual work can start with installing and configuring the HMC.
The required LPARs with specified CPU, Memory, NW Interfaces and Storage can be defined. The VIO server(s) will be configured on the allocated LPARs and resources for the new LPAR will be defined.
The approach would be to clone the existing server and upgrade the image to the required newer OS level. A NIM server will be built (assuming no NIM server is available) and configured with the reqquired evel of LPP Source and SPOT needed for the new server, after which the cloning and migration procedure will be worked on.
The procedure to powerup and configure the HMC is provided in the document “Configuring the HMC”