Chapter 26. Using snapshots on Stratis file systems You can use snapshots on Stratis file systems to capture file system state at arbitrary times and restore it in the future. 26.1. Characteristics of Stratis snapshots In Stratis, a snapshot is a regular Stratis file system created as a copy of another Stratis file system. The snapshot initially contains the same file content as the original file system, but can change as the snapshot is modified. Whatever changes you make to the snapshot will not be reflected in the original file system. The current snapshot implementation in Stratis is characterized by the following: A snapshot of a file system is another file system. A snapshot and its origin are not linked in lifetime. A snapshotted file system can live longer than the file system it was created from. A file system does not have to be mounted to create a snapshot from it. Each snapshot uses around half a gigabyte of actual backing storage, which is needed for the XFS log. 26.2. Creating a Stratis snapshot You can create a Stratis file system as a snapshot of an existing Stratis file system. Prerequisites Stratis is installed. See Installing Stratis . The stratisd service is running. You have created a Stratis file system. See Creating a Stratis file system . Procedure Create a Stratis snapshot: Additional resources stratis(8) man page on your system 26.3. Accessing the content of a Stratis snapshot You can mount a snapshot of a Stratis file system to make it accessible for read and write operations. Prerequisites Stratis is installed. See Installing Stratis . The stratisd service is running. You have created a Stratis snapshot. See Creating a Stratis file system . Procedure To access the snapshot, mount it as a regular file system from the /dev/stratis/ my-pool / directory: Additional resources Mounting a Stratis file system mount(8) man page on your system 26.4. Reverting a Stratis file system to a snapshot You can revert the content of a Stratis file system to the state captured in a Stratis snapshot. Prerequisites Stratis is installed. See Installing Stratis . The stratisd service is running. You have created a Stratis snapshot. See Creating a Stratis snapshot . Procedure Optional: Back up the current state of the file system to be able to access it later: Unmount and remove the original file system: Create a copy of the snapshot under the name of the original file system: Mount the snapshot, which is now accessible with the same name as the original file system: The content of the file system named my-fs is now identical to the snapshot my-fs-snapshot . Additional resources stratis(8) man page on your system 26.5. Removing a Stratis snapshot You can remove a Stratis snapshot from a pool. Data on the snapshot are lost. Prerequisites Stratis is installed. See Installing Stratis . The stratisd service is running. You have created a Stratis snapshot. See Creating a Stratis snapshot . Procedure Unmount the snapshot: Destroy the snapshot: Additional resources stratis(8) man page on your system

Commands:
stratis fs snapshot my-pool my-fs my-fs-snapshot
mount /dev/stratis/ my-pool / my-fs-snapshot mount-point
stratis filesystem snapshot my-pool my-fs my-fs-backup
umount /dev/stratis/ my-pool / my-fs stratis filesystem destroy my-pool my-fs
stratis filesystem snapshot my-pool my-fs-snapshot my-fs
mount /dev/stratis/ my-pool / my-fs mount-point
umount /dev/stratis/ my-pool / my-fs-snapshot
stratis filesystem destroy my-pool my-fs-snapshot