Detaching and re-attaching Oracle dSources

Overview

Each dSource contains metadata that associates it with the source database, as well as the data it has ingested from the source database in the form of snapshots up to that point. It is possible to detach, or unlink, a dSource from its source database. This breaks the association with the source database without affecting the data within the Delphix Engine. Detached dSources and their source databases have these properties:

• A detached dSources can still be used to provision a virtual database (VDB).

• You can re-link the source database as a different dSource.

Prerequisites

Before detaching an Oracle dSource, you must capture the following RMAN configuration:

• Level or SCN based backups

• Data load channel settings: number of channels and files per channel

A dSource can only be attached to a new data source once it has been unlinked.The above RMAN configuration will be removed once the dSource is unlinked.

When attaching an Oracle dSource to a new data source, the new data source must be the same logical database satisfying the following constraints:

• Same dbid

• Same dbname

• Same creation time

• Same resetlogs SCN

• Same resetlogs time

• Same redo stream, where a log must exist with

  • Same sequence

  • Same thread

  • Same end SCN

For Oracle dSources, this procedure can be used to initially link from a standby server that is faster or less disruptive, unlink the dSource, and then attach it to the production server for subsequent incremental SnapSync operations. When you perform the attach operation, you will need the source config name of an unlinked database.

It is possible to link a Single Instance Oracle database, unlink from it, and link to a RAC cluster and vice versa as long as the instances are for the same database. For example, initially link a Single Instance standby database of a RAC primary database, unlink the dSource, and then link the RAC primary database itself or another RAC standby database to the same dSource.

Detaching a dSource

1. Login to the Delphix Management application as a user with OWNER privileges on the dSource, group, or domain.

2. Select Manage > Datasets.

3. Select the database you want to unlink or delete.

4. From the Actions menu (...) select Unlink. A warning message will appear.

5. Click Unlink to confirm.

If you are detaching an Oracle CDB dSource, you must first detach all dependent PDBs in that CDB before you can detach the CDB.

To detach a dSource via CLI, see Detaching and Attaching an Oracle dSource via CLI.

Rebuilding source databases and using VDBs

In situations where you want to rebuild a source database but retain the existing dSource, you will need to detach the original dSource and create a new one from the rebuilt data source.

1. Detach the dSource as described in the procedure on this page.

2. You cannot attach a dSource with the same name as a dSource that is already attached. If you intend to give the new dSource the same name as the original one, rename the detached dSource.

   1.  At the top of the Configuration tab, next to the dSource's name, click the Edit (pencil) icon.

   2.  After renaming the dSource, click the green checkmark.

3. Create the new dSource from the rebuilt database.

You will now be able to provision VDBs from both the detached dSource and the newly created one, but the detached dSource will only represent the state of the source database prior to being detached.

Attaching a previously detached dSource

You can only re-attach databases that represent the same physical database.

Via GUI

To attach a dSource back into the Delphix Engine via GUI, from the Delphix Management application:

1. Select Manage > Datasets.

2. Select your dSource.

3. From the Actions menu (...) select Link dSource.

4. In the Link dSource dialog, fill in the information corresponding to the new dSource as well as its new environment.
   

   

5. Click Link.

Via CLI

To attach a dSource back into the Delphix Engine via CLI:

1. Login to the Delphix CLI as delphix_admin or a user with OWNER privileges on the dSource, group, or domain.

2. Select the dSource by name using database select .

3. Run the attachSource command.

4. Set the source config you want to attach to, using set attachData.config=. Source configs are named by their database unique name.

5. Set any other source configuration operations as you would for a normal link operation.

6. Run the commit command.

Backup mode for sttaching Oracle dSources

For Oracle dSources, the SnapSync backup option should be set to SCN Backup mode. Level Backup mode is based on information stored in the database control file. If the control file of the newly attached database does not contain information about the previous backups, an initial backup will be created. In addition, Block Change Tracking will not be in sync, and the next SnapSync will need to read the entire database to determine which blocks have changed. See Advanced Data Management Settings for Oracle dSources for more information about Backup Mode.