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Delphix

TB045 PDB Failover Process Results in Non-Provisionable Snapshots

 

 

Alert Type

Data Availability

Background

After an Oracle Data Guard switchover/failover of a database, it may be desired for the dSource to be connected to the new standby database ( or primary if it was originally connected to the primary ). If the dSource is a PDB, the recommended procedure to achieve this is to unlink the PDB from the original dSource and link the PDB to the new dSource. The process is documented here - KBA1103 Oracle Data Guard Switchover and Delphix dSources

Following this procedure may result in all subsequent snapshots reporting missing archive logs. These snapshots will not allow provisioning to the snapshot or any point in time.

This is not an indication of any fault with the Primary or Standby database itself. This issue only occurs if the dSource is a PDB/CDB.

Impact

After the role change in the source database and the attaching of the dSource to the new site location, snapshots from the PDB will not be provisionable.

Contributing Factors

The issue may occur in the following Delphix Engine Versions:

Major Release

All Sub Releases

5.2

5.2.2.0, 5.2.3.0

5.1

5.1.0.0, 5.1.1.0, 5.1.2.0, 5.1.3.0, 5.1.4.0, 5.1.5.0, 5.1.5.1, 5.1.6.0, 5.1.7.0, 5.1.8.0, 5.1.8.1, 5.1.9.0

5.0

5.0.1.0, 5.0.1.1, 5.0.2.0, 5.0.2.1, 5.0.2.2, 5.0.2.3, 5.0.3.0, 5.0.3.1, 5.0.4.0, 5.0.4.1 ,5.0.5.0, 5.0.5.1, 5.0.5.2, 5.0.5.3, 5.0.5.4

Symptoms

After linking a PDB to a different source database, snapshots may report missing logs, taking further snapshots does not resolve this issue. 

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Relief/Workaround

The options to resolve this issue are

1. Switch DataGuard environment back to the original configuration, then link the PDB back to the original CDB.

2. Unlink and rename the problem PDB, then Add PDB from environments. Note this process will create a new dSource, effectively doubling the space required on the system. If no VDBs are provisioned and it is not required, the old PDB could be deleted.

3. Leave the PDB linked to the same source database. If the database role is now a standby, the PDB may need to be placed in "open read only" mode or the database user set to "sys". 

Resolution

This issue will be resolved in a future release.