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, "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.
Size: The current copy size is the amount of space used on the Delphix engine by the VDBs data but across all Timeflows.
DB Logs: archive log files
Temp Files: tempfiles