Database migrations are often necessary when applications outgrow their current databases, when businesses move away from legacy technology, or when the existing database no longer fits the application's needs. These migrations can be simplified using tools like CockroachDB, which offers a schema conversion tool and support for AWS DMS (Database Migration Service). The schema conversion tool helps migrate schema from databases such as PostgreSQL to CockroachDB by identifying necessary changes for optimal performance in a distributed system. AWS DMS facilitates data transfer between endpoints, even if only one is on AWS, using CockroachDB's PostgreSQL wire compatibility. This process typically involves creating a replication instance, setting up source and target endpoints, and creating a migration task. CockroachDB's offerings aim to make database migrations faster and easier, supported by detailed documentation and community resources for users seeking to transition to distributed databases.