Amazon VPC Flow Logs is now available in the Sao Paulo region. VPC Flow Logs is a feature that enables you to capture information approximately the IP traffic going to and from your VPC. Once enabled for a particular VPC,VPC subnet or Elastic Network Interface (ENI), relevant network traffic will be logged to CloudWatch Logs for storage and analysis by your own applications or third-party tools. Additionally, and metrics can be created to identify trends and patterns.
Source: amazon.com