A company runs a highly available SFTP service on two EC2 Linux instances with elastic IP addresses and shared storage. User accounts are Linux users on the servers. The company wants a serverless option that provides high IOPS performance, highly configurable security, and maintains control over user permissions. Which solution meets these requirements?

The correct solution uses AWS Transfer Family for SFTP, which is a fully managed, serverless service that supports SFTP. Amazon EFS provides high IOPS performance and shared storage, fulfilling the requirement for high IOPS and shared storage that can be attached to the Transfer Family endpoint. Using a VPC endpoint with internet-facing access and a security group allows for highly configurable security and control over trusted IP addresses. User permissions are managed within AWS Transfer Family, maintaining control. Incorrect options: EBS volumes cannot be directly attached to AWS Transfer Family endpoints. EBS is block storage for a single EC2 instance. S3 buckets, while attachable to AWS Transfer Family, do not inherently provide the high IOPS performance typically associated with file systems for SFTP workloads, and managing user permissions directly on S3 for SFTP users can be more complex than with EFS. An S3 bucket with an internal access VPC endpoint would not allow external SFTP clients to connect, failing the requirement for an accessible SFTP service.