Within the Delphix Timeflow, incremental restore points are called Snapshots. Delphix Snapshots use a shared block architecture to provide all the functionality of daily full backups using only a tiny percentage of the storage for full backups. Because shared block architectures are not common, a "common sense" understanding of how storage is associated with a Snapshot can be misleading.
The size of a Snapshot is defined to be the size of changes that are unique to that Snapshot. In other words, changed blocks that are only associated with that one Snapshot.
The latest Snapshot will always have 0 sizes initially, as there are no changes associated with it, nothing has changed since the Snapshot was taken, so there is no space used by unique changes.
A block can be shared by multiple Snapshots if the block has not changed between the creation of those Snapshots. Any blocks that are shared amongst multiple Snapshots are accounted for in the shared Snapshot Space total.
The following screenshot provides an example of disk usage.
Current Copy Size: The current copy size is the amount of space used on the Delphix Engine by the VDBs data but across all the Time flows.
DB Log Size: The DB log size is the size for archive log files.
Temp File Size: This field is currently not active (for future use).
Container Size: The container size is the size of the whole dataset.
Total Snapshot Size: The total snapshot size is the size of all snapshots combined, including anything shared.
Shared snapshot space: The shared snapshot space is the space shared by snapshots.