You have a few very large (90 GB) files to load to Google Cloud and will provide bandwidth for the initial transfer. Transactional systems must continue updating the warehouse in real time. Which tools do you use for bulk migration and ongoing writes?

gsutil is the most appropriate tool for bulk migration of large files (90 GB) directly to Cloud Storage, offering robust transfer capabilities and resuming interrupted transfers. Pub/Sub is the standard Google Cloud service for ingesting real-time event streams, acting as a highly scalable message broker. Dataflow is an excellent choice for processing these real-time streams, providing a fully managed service for executing Apache Beam pipelines, which can transform and load data into a data warehouse like BigQuery. Storage Transfer Service is designed for large-scale, automated transfers between storage systems (e.g., AWS S3 to Google Cloud Storage), not typically for direct uploads from local systems. BigQuery Data Transfer Service is for transferring data into BigQuery from other sources, not for initial file uploads to Cloud Storage. Dataproc is a managed Apache Hadoop and Spark service, suitable for batch processing, but Dataflow is generally preferred for real-time stream processing due to its autoscaling and unified batch/stream model. Using gsutil for real-time updates is incorrect as it's a command-line utility for file transfers, not a streaming ingestion mechanism.