System Migration

Overview

Provides comprehensive guidance for system-level migrations including operating system changes, hardware platform transitions, mainframe modernization, virtualization, and data center migrations. Focuses on system infrastructure that underlies applications and platforms.

Key Points:

• System migrations often involve multiple skills: OS + database + application coordination
• Plan for 30-50% more time than initial estimates
• Parallel run periods reduce risk but increase cost
• Mainframe migrations are typically multi-year projects
• Physical to virtual conversions rarely have issues with modern hardware
• Always validate hardware compatibility before OS migrations

Workflow Decision Tree

Choose your migration path based on the system type:

1. Operating System Migration

Use for: Linux distribution changes, Windows to Linux, OS version upgrades Load: migration-types.md for detailed workflows

2. Hardware Platform Migration

Use for: Mainframe to x86, architecture changes, system consolidation Load: migration-types.md for platform-specific guidance

3. Virtualization Migration

Use for: Physical to Virtual (P2V), Virtual to Virtual (V2V), cloud migrations Load: migration-types.md for virtualization patterns

4. Data Center Migration

Use for: Facility moves, infrastructure consolidation, hybrid cloud Load: migration-types.md for data center procedures

Standard Migration Workflow

Phase 1: Assessment & Planning

1. Document current system state (OS version, kernel, packages, services, configurations)
2. Identify application and hardware compatibility requirements
3. Determine migration strategy (in-place upgrade vs fresh install)
4. Create detailed migration plan with timeline and resources

Phase 2: Preparation

1. Complete full system backups (OS, configurations, data)
2. Set up target system environment
3. Test migration procedures in non-production
4. Prepare rollback plan and validation criteria

Phase 3: Execution

1. Perform migration following tested procedure
2. Migrate configurations and customize for target system
3. Install and configure applications
4. Validate system functionality

Phase 4: Validation & Cutover

1. Run validation tests (See validation-and-testing.md)
2. Conduct parallel run period if applicable
3. Execute cutover to production
4. Monitor closely post-migration

Core Best Practices

✅ Thorough Testing - Test everything in non-production environments first ✅ Complete Backups - Multiple backups at different stages before migration ✅ Automation - Script repeatable tasks to reduce errors and ensure consistency ✅ Gradual Migration - Migrate in phases, not all at once ✅ Rollback Plan - Always have a tested way to revert changes ✅ Documentation - Document every configuration, decision, issue, and resolution

Reference Files

Load these reference files based on specific migration needs:

• Migration Types: See migration-types.md when:

  • Planning OS migrations (Linux distro changes, Windows to Linux)
  • Executing hardware platform migrations (mainframe to x86)
  • Performing virtualization migrations (P2V, V2V)
  • Conducting data center migrations

• System Configuration Migration: See system-configuration-migration.md when:

  • Migrating network configurations
  • Transferring user accounts and permissions
  • Moving system services and cron jobs
  • Replicating firewall and security settings

• Validation and Testing: See validation-and-testing.md when:

  • Designing test plans for migrations
  • Validating system functionality post-migration
  • Conducting performance benchmarking
  • Testing disaster recovery procedures

• Rollback Procedures: See rollback-procedures.md when:

  • Planning rollback strategies
  • Migration fails or encounters critical issues
  • Need to revert to original system state

• Tools and Resources: See tools-and-resources.md when:

  • Selecting migration tools (rsync, dd, clonezilla, etc.)
  • Choosing automation frameworks
  • Need monitoring and validation utilities

• Best Practices: See best-practices.md when:

  • Need comprehensive checklist for migration execution
  • Planning communication and stakeholder management
  • Establishing monitoring and alerting strategies

• Anti-Patterns: See anti-patterns.md when:

  • Need to avoid common migration mistakes
  • Reviewing migration plans for potential issues
  • Troubleshooting failed or problematic migrations