Incremental Migration to Vercel

When migrating to Vercel you should use an incremental migration strategy. This allows your current site and your new site to operate simultaneously, enabling you to move different sections of your site at a pace that suits you.

In this guide, we'll explore incremental migration benefits and different strategies.

Incremental migrations offer several advantages:

• Reduced risk due to smaller migration steps
• A smoother rollback path in case of unexpected issues
• Earlier technical implementation and business value validation
• Downtime-free migration without maintenance windows

One-time migration involves developing the new site separately before switching traffic over. This approach has certain drawbacks:

• Late discovery of expensive product issues
• Difficulty in assessing migration success upfront
• Potential for reaching a point of no-return, even with major problem detection
• Possible business loss due to legacy system downtime during migration

Despite requiring more effort to make the new and legacy sites work concurrently, incremental migration is beneficial if:

• Risk reduction and time-saving benefits outweigh the effort
• The extra effort needed for specific increments to interact with legacy data doesn't exceed the time saved

With incremental migration, legacy and new systems operate simultaneously. Depending on your strategy, you'll select a system aspect, like a feature or user group, to migrate incrementally.

This strategy targets system features with the following process:

1. Identify all legacy system features
2. Choose key features for the initial migration
3. Repeat until all features have been migrated

Throughout, both systems operate in parallel with migrated features routed to the new system.

This strategy focuses on system users with the following process:

1. Identify all user groups
2. Select a user group for initial migration to the new system
3. Repeat until all users have been migrated

During migration, a subset of users accesses the new system while others continue using the legacy system.

A blend of vertical and horizontal strategies. For each feature subset, migrate by user group before moving to the next feature subset.