system-migration

What this skill does

# 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](references/migration-types.md) for detailed workflows

### 2. Hardware Platform Migration

**Use for:** Mainframe to x86, architecture changes, system consolidation
**Load:** [migration-types.md](references/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](references/migration-types.md) for virtualization patterns

### 4. Data Center Migration

**Use for:** Facility moves, infrastructure consolidation, hybrid cloud
**Load:** [migration-types.md](references/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](references/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](references/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](references/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](references/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](references/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](references/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](references/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](references/anti-patterns.md) when:
  - Need to avoid common migration mistakes
  - Reviewing migration plans for potential issues
  - Troubleshooting failed or problematic migrations