Amazon Web Services, the biggest public cloud around, announced Amazon Elastic File System today. This is a new cloud service companies can call on to set up and share their file systems.

AWS head Andy Jassy announced the feature toward the end of a keynote at the 2015 San Francisco AWS Summit. A preview of the service will become available this summer, Jassy said.

The system, which supports NFSv4, can store a petabyte of data or more, Jassy said. And you only pay for what you use — it can become larger or smaller dynamically, he said. The service automatically adjusts network throughput and storage IOPS (in out per second), so admins don’t need to worry about that work, Jassy said.

An Amazon blog post has more on the new feature.