Snapshots are a block image in the form of a storage volume or LUN that is used to instantly capture the state of a volume at a specific point in time. PowerFlex snapshots are thin-provisioned and writable, unless you use the PowerFlex Secure Snapshot or read-only options. After you take a snapshot, it becomes a new unmapped volume in the system. You can treat the snapshot like any other volume exposed by the storage system; it can be mapped, unmapped, renamed, resized, and so on.
When creating a snapshot, you can set snapshots as secure, which enables customers to meet requirements for data retention. After a snapshot is created with the secure option, it cannot be altered or deleted until the assigned expiration time is reached.
You can initiate and manage PowerFlex snapshots manually through the UI, CLI, or REST API client. The CLI, REST API, and UI (after version 3.6) also enable snapshot policies, which automate the creation, retention and deletion of snapshots according to predefined schedules.
Snapshots and their source volume are organized into a Volume Tree (V-Tree). the V-Tree includes the root volume and all descendant snapshots resulting from that volume. A V-Tree includes not only snapshots taken of the root volume at different points in time, but also descendants that are snapshots of snapshots.