Dell PowerVault ME5 Series Administrator's Guide

Snapshot trees

Because a snapshot can be the source of other snapshots, a single volume can be the progenitor of many levels of snapshots.

Originating from an original base volume, the levels of snapshots create a snapshot tree that can include up to 254 snapshots, each of which can also be thought of as a leaf of the tree. When snapshots in the tree are the source of additional snapshots, they create a new branch of the snapshot tree and are considered the parent snapshot of the child snapshots, which are the leaves of the branch.

The tree can contain snapshots that are identical to the volume or have content that has been later modified. Once the 254-snapshot limit has been reached, you cannot create additional snapshots of any item in the tree until you manually delete snapshots from the tree.

You can only delete snapshots that do not have any child snapshots. You can expand the base volume of a snapshot tree, but you cannot expand any snapshots in the tree.