File Gateway, part of the AWS Storage Gateway service, now publishes health and performance logs and metrics to Amazon CloudWatch, providing you with continuous visibility into operations of your gateway in order to quickly respond to changes in your workload.

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/09/aws-storage-gateway-adds-amazon-cloudwatch-logging-and-metrics-for-file-gateway/