Stratis is one of the new features that ships with RHEL distribution. Stratis is a local storage management solution that focuses on simplicity and improved usability while at the same time providing access to advanced storage features. It uses the XFS file system and grants you access to advanced storage capabilities such as:
Thin provisioning
File system snapshots
Tiering
Pool-based management
Monitoring
Basically, Stratis is a storage pool that is created from one or more local disks or disk partitions. Stratis helps a System administrator set up and manage complex storage configurations.