Taking a Snapshot
On initiating a sync, Delphix Engine checks the staging server for the database of the given name and if a match is found, it then takes a snapshot of its data files. Before and after taking the snapshot, Delphix Engine runs a few validations to check the readiness and consistency of the database for the snapshot.
Below are the checks performed by Delphix Engine during snapshot operation:
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The staging database is in the
MOUNT,READ ONLYorREAD ONLY WITH APPLYmode -
All data files are present on the Delphix Engine mounted storage
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For a non-standby staging database, checkpoint SCN of all online datafiles is the same
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The database must be recovered and no data files must be in
FUZZYstate -
Checkpoint SCN must have advanced since the last snapshot was taken
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Checkpoint SCN has not advanced during the snapshot operation
CDB dSource snapshots cannot be taken manually. A PDB dSource snapshot operation takes a CDB dSource snapshot first before taking a PDB snapshot.
Taking an incremental snapshot
The staging database can be populated further by:
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Restoring incremental backups
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Through ongoing managed recovery in case of Physical Standby databases
After the staging database is populated with incremental changes, a snapshot operation will take an incremental snapshot of the dSource.