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 size 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: is the size of the how much space would be needed to store the database as it exists right now, without snapshots, logs etc. (So if you were going to V2P the database without any logs it would be the amount of storage needed on the target server.)
DB Logs: archive log files
Temp Files: tempfiles