Logical Migration (Storage Clone) – AIX LPAR Migration Procedure

Introduction:

This document outlines the procedure for performing a logical migration of an existing AIX LPAR to a new target LPAR using storage-level cloning. Unlike traditional mksysb or alt_disk_copy approaches, this method leverages SAN-based LUN cloning to create an exact replica of the source system’s root and data volumes.

The primary benefit of this method is minimal downtime: the source system remains fully operational until the final cutover, and the cloned target environment can be booted and validated independently before switching over. This approach is particularly useful in environments where rapid migrations or environment replication are required, while ensuring consistent data integrity and system configuration.

Objective:

• Perform a logical migration of an AIX LPAR to a new target LPAR.
• Utilize SAN-based storage cloning for fast, block-level replication.
• Enable the target LPAR to boot and operate independently before final cutover.
• Minimize downtime during migration.

Scope:

• Migration at the logical level from source LPAR to target LPAR.
• Cloning of rootvg and application datavg volumes via SAN.
• Target environment is validated and ready for production before final switchover.

Pre-Requisites:

• Access to the HMC to create and manage LPAR profiles.
• Storage team capable of performing LUN cloning and mapping.
• Network configuration details for the new LPAR (hostname, IP, VLAN, DNS).
• Coordination with application/database owners for controlled shutdown/startup.

Step-by-Step Migration Procedure:

1. Create Target LPAR

1.1 In HMC, create a new LPAR profile with:

• Same CPU and memory configuration as the source (or as required by SLA).
• Correct virtual FC adapters / NPIV configuration for SAN access.
• Correct virtual Ethernet adapters for network VLANs.

2. Provide WWNs to Storage Team

Share target LPAR WWPNs with storage team for LUN mapping.

Verify login WWPNs on target LPAR:

# chnportlogin -m <manage_system> -o login -p <LPAR>

# lsnportlogin -m <manage_system> --filter "lpar_names=<LPAR>"

3. Storage Team: Clone Source Disks

• Storage team creates new LUNs of equal size as source’s rootvg and datavg.
• Perform block-level cloning using SAN features (e.g., TimeFinder, SnapVX, SRDF).
• Map cloned LUNs to the target LPAR using provided WWPNs.

4. Boot Target LPAR from Cloned LUNs

In HMC, boot the target LPAR into SMS menu.

Select cloned rootvg disk as startup device.

Boot into AIX and verify:

# bootlist -om normal

Ensure the cloned disk (usually hdisk0) is set as the normal boot device.

5. Network and Host Configuration

Verify hostname:

# hostname

Update /etc/hosts, /etc/networks, network interface files.

Configure new IP:

# chdev -l en0 -a netaddr=<new_ip> -a netmask=<mask> -a gateway=<gateway>

Update /etc/resolv.conf and DNS if required.

6. System Validation on Target LPAR

Perform OS-level verification:

# lsvg

# lsvg -p rootvg

# lsvg -p datavg

# df -g

# lspv

# lsvg -o

Ensure volume groups, disks, and logical volumes are healthy.

7. Application & Database Coordination

Inform application and database teams to stop services on source LPAR before cutover.

8. Cutover Execution

Shutdown source LPAR cleanly:

# shutdown -F

Update DNS to point to target LPAR IP.

Start databases and applications on target LPAR.

Validate system and application functionality.

9. Post-Migration Verification

Confirm target boots from cloned rootvg:

# bootlist -om normal

Validate network, routing, and system logs:

# netstat -rn

# ifconfig -a

# errpt -a | more

# tail -f /var/adm/messages

Fallback / Rollback Plan — Logical Migration (AIX LPAR):

Purpose:

To restore operations to the original source LPAR in case of a failure during migration or if post-migration validation on the target LPAR identifies critical issues. This ensures rapid restoration of services with minimal downtime and data loss.

Fallback Procedure:

1. Shutdown Target LPAR

Stop all applications and database services gracefully on the target LPAR.

Shutdown the LPAR:

# shutdown -F

Confirm the LPAR is powered off via HMC or CLI:

# lssyscfg -r lpar -m <managed_system> -F name,state

2. Revert DNS Configuration

Update DNS records to point back to the source LPAR IP address.

Confirm that clients and network services will resolve to the original source.

3. Start Source LPAR

Power on the source LPAR from HMC or CLI:

# chsysstate -r lpar -m <managed_system> -o on -n <source_LPAR>

Verify the system boots successfully and rootvg disks are accessible.

4. Mount Filesystems

Ensure all volume groups and filesystems are mounted:

# mount -a

# df -g

5. Start Database and Applications

• Start database and application services on the source LPAR.
• Validate application and database accessibility to confirm full service restoration.

Notes:

• Keep the target LPAR powered off until the issue is resolved to avoid conflicts with IPs, DNS, or shared storage.
• Document any errors observed on the target LPAR for post-mortem analysis.
• After successful rollback, the migration plan can be revisited and corrected before re-attempt.