RealityMine collects digital user behavior data to help companies with marketing, product development, and analyzing user patterns. They are migrating from an on-premise SQL Server data warehouse to Amazon Redshift to handle doubling data volumes. Redshift provides better performance and scalability at lower cost compared to other options. It requires extracting raw data from SQL Server without encoding issues, loading to S3, and transforming in Redshift using a star schema with careful consideration of distribution and sort keys for query performance. Ongoing database maintenance and backups are also different in Redshift.