Perform V2P operation on Oracle VDB or vPDB in-place to Physical Filesystem

Overview

This article describes how to perform the V2P operation or an in-place conversion of a virtual database (VDB) or a virtual pluggable database (vPDB) into a physical database stored on a physical filesystem. No intermediate storage is needed; the database files are moved directly from Delphix to the physical filesystem.

This procedure can be used to perform V2P operation on an Oracle VDB or vPDB in a Linked CDB to a physical filesystem.

Limitation

In order to perform the V2P operation to filesystem, select a directory location which supports direct IO operations.

If providing the target dir as /tmp is unavoidable, set the following initialization parameter:

ALTER SYSTEM SET FILESYSTEMIO_OPTIONS=ASYNCH SCOPE=SPFILE;

With asynchronous I/O, the OS itself performs I/O on behalf of Oracle software in a highly efficient and parallel manner. OS buffer cache is used for I/O instead of Oracle’s own buffer cache within the SGA.

This value, however, may not be what Oracle recommends for this parameter.

Prerequisites  

1. The following conditions must be met prior to the V2P operation. The operation will fail if any of these conditions are not met: 

   1. Sufficient storage space must be available in the target filesystem for datafiles. 

   2. If the V2P operation is initiated from a vPDB, and a new PDB name is specified: 

      1. it must meet all the naming constraints defined in the Oracle documentation.

      2. it must be different from the existing PDBs in the target CDB.

   3. If the V2P operation is initiated from a VDB, and a new database unique name is specified:

      1. it must meet all the naming constraints as defined in the Oracle documentation.

      2. it must be different from the database unique name of any other database on the same target host.

      3. it must not be a RAC database.

   4. No offline datafiles or tablespaces must exist in the VDB or vPDB.

   5. The VDB or vPDB on which the V2P operation is initiated must be Open. 

   6. The V2P operation on a VDB in a RAC environment must be performed as the Oracle user, otherwise the operation will fail. This is required because Delphix issues srvctl commands to configure the resulting physical database in RAC and these commands can only be run with Oracle user privileges

   7. No other job must be running on the virtual pluggable database or its associated environment. 

   8. For the V2P operation on a VDB or vPDB in a RAC environment, ensure that the states of all the cluster nodes are displayed as 'Enabled' in the Delphix management GUI. If one of the cluster nodes is disabled, the V2P operation will fail, although the physical copy would have been completed and would be usable, the VDB or vPDB will need to be force disabled manually. 

   9. The VDB or vPDB must have a provisionable snapshot, otherwise the operation will fail with the following message: Cannot find a point in the TimeFlow for the semantic location "LATEST_POINT". 

2. To perform the V2P operation on a vPDB in a vCDB, the vPDB must be migrated to a Linked CDB and then enabled, or alternatively, provision a child vPDB from this vPDB snapshot to a linked CDB and then perform the V2P operation. 

Procedure 

1. Delphix takes a new snapshot of the virtual database/pluggable database before starting the V2P operation. Also, Delphix retains the timeflow and all its snapshots after the V2P operation is completed. After the V2P operation, the virtual source can be easily migrated and rewound to the previously created snapshots. 

2. It is recommended that the V2P operation be performed on a newly provisioned VDB or vPDB, although it can still be performed on your existing VDB or vPDB. The reason is that it simplifies the post V2P process to re-enable the existing VDB or vPDB. 

3. Refer to Virtual to Physical (V2P) operation for a multitenant virtual pluggable Oracle database to ASM or Physical Filesystem or Virtual to Physical (V2P) operation for a non-multitenant virtual Oracle database to ASM or Physical Filesystem for the procedure.

Considerations after the successful V2P operation on a VDB or vPDB to Physical Filesystem 

After the V2P operation is successful, no Delphix operations are allowed on the VDB or vPDB except migration or a fresh provision of a new child VDB or vPDB. However, there may be situations where you may need to re-enable the VDB or vPDB, please perform a migration of the vPDB to a different host and CDB and then rewind the VDB or vPDB to its latest snapshot.

Option 1: After the successful V2P operation on a VDB to replace a linked physical database that is damaged and is unusable with new physical database having the same name, same unique name and same SID as the original damaged database, the new physical database can be linked back to Delphix engine using the following steps: 

1. Delete or Migrate the VDB that was used to create a new physical database to a different environment. 

2. Refresh the environment where the new physical database is created.

3. Detach the dSource from the original source database. 

4. Force attach the dSource to the newly created physical database

Option 2: After the successful V2P operation on a vPDB with the new physical PDB name that is the same as the vPDB name, the new physical PDB can be linked back to Delphix engine using the following steps:

1. Delete or migrate the vPDB to a different CDB.

2. Refresh the environment where the new physical PDB is created.

3. Detach the dSource PDB from the original source PDB.

4. Force attach the dSource to the newly created physical PDB.