Identify which VM instances and traffic types cause a daily network usage spike in the project while minimizing cost and management overhead. What should you do?

Enabling VPC Flow Logs and sending them to BigQuery is the most effective solution for identifying network usage spikes. VPC Flow Logs capture all network flow information (source, destination, ports, protocols, bytes, etc.) for VM instances, providing comprehensive data for analysis in BigQuery. This built-in Google Cloud feature is cost-effective and requires minimal management overhead. Firewall Rules Logging only records traffic that hits a firewall rule, not all network traffic, making it insufficient for comprehensive usage analysis. Packet Mirroring is resource-intensive and designed for deep packet inspection, not broad network usage monitoring, and requires significant management. Deploying a third-party appliance introduces additional cost, complexity, and management overhead, and may not provide the granular, per-VM insights needed.