Home > Storage > PowerMax and VMAX > Data Protection > Dell EMC PowerMax and VMAX All Flash: TimeFinder SnapVX Local Replication > Local replication with SnapVX
Local replication with SnapVX starts out as efficiently as possible by creating a snapshot, a pointer-based structure that preserves a point-in-time view of a source volume. Snapshots do not require target volumes, share back-end allocations with the source volume and other snapshots of the source volume, and only consume additional space when the source volume is changed. A single source volume can have up to 1024 snapshots.
Each snapshot has a user-defined name and can optionally have an expiration date, both of which can be modified at any time. Management interfaces enable the user to take a snapshot of an entire SG with a single command.
A point-in-time snapshot can be accessed by linking it to a host accessible volume referred to as a target. The target volumes are standard Thin LUNs. Up to 1024 target volumes can be linked to the snapshots of a single source volume. This limit can be achieved either by linking all 1024 target volumes to the same snapshot from the source volume, or by linking multiple target volumes to multiple snapshots from the same source volume. However, a target volume may only be linked to a single snapshot at a time.
By default, targets are linked in a nocopy mode, but can be linked in a copy mode to create full-copy clones. Snapshots can be cascaded from linked targets, and targets can be linked to snapshots of linked targets. There is no limit to the levels of cascading and the cascade can be broken at any point, with limitations that are discussed later.