Backup a CDB/PDB

• To make a database backup you need the SYSBACKUP or SYSDBA privilege.
• You can backup the CDB and all the PDBs independantly, all together, or by specifying a list.
• You can backup a PDB by connecting directly to it and use:
  • RMAN> BACKUP DATABASE:
• You can backup a PDB by connecting to the CDB and use:
  • RMAN> BACKUP PLUGGABLE DATABASE MY_PDB;
• To backup only the root (CDB$ROOT) connect to the CDB and use:
  • RMAN> BACKUP DATABASE ROOT;
• You can backup everything by connecting to the CDB and use:
  • RMAN> BACKUP DATABASE;
• You can backup only some PDBs by using:
  • RMAN > BACKUP PLUGGABLE DATABASE PDB1, PDB2, PDB3;

Backup tablespaces and datafiles in CDBs/PDBs

• You can backup tablespaces from several PDBs at the same time when connected to the root using:
  • RMAN> BACKUP TABLESPACE PDB1:USERS, PDB2:TOOLS, PDB3:SYSTEM;
• You can also backup tablespaces using the standard command when you connect directly to the PDB:
  • RMAN> BACKUP TABLESPACE SYSTEM;
• To backup datafiles for a PDB you can :
  • Connect to the root and use : BACKUP DATAFILE 12,13,14;
  • Connect to the PDB and use : BACKUP DATAFILE 12,13,14;

Continue reading OCP 12C – Backup, Recovery and Flashback for a CDB/PDB →

Connecting to a CDB or PDB

• Connecting to a CDB or PDB is not different of connecting to a standard database.
• When you create a PDB, it is automatically assigned a service which can be used to reach this specific PDB.
• You can either use the EZ connect syntax, the Oracle Net Service syntax or the new : ALTER SESSION SET CONTAINER syntax.
• The CDB_SERVICES view lets you view the services for each PDB.
• The SHOW CON_NAME command can be used to identify the container your are connected to.

Users and administrative tasks

• Only a common user can connect to CDB$ROOT.
• To use the ALTER SESSION SET CONTAINER command, a common user must have the SET CONTAINER privilege.
• All management tasks except PLUG/UNPLUG and STOP/START  in a PDB are equivalent to a standard database.
• You can use the CONTAINER=ALL clause in a DDL statement to execute it in all PDBs. This can only be done by a common user with the SET CONTAINER privilege.
• By DEFAULT when you issue a DDL the CONTAINER clause is equal to CURRENT.
• A common user name starts wth C##

Continue reading OCP 12C – Managing CDBs and PDBs →

The multitenant architecture

• Needs enterprise edition and the multitenant option.
• Consists of a CDB (Container database) and zero, one or up to 252 PDBs (pluggable databases).
• Has a root container (the CDB itself) and a seed container (template to create PDBs)
• There is only one instance per CDB.
• A PDB doesn’t have :
  • background processes
  • undo tablespace, it uses the CDB’s.
  • redologs, it uses the CDB’s.
  • controlfiles
• A PDB have :
  • It’s own tablespaces
  • It’s own local users and local roles
  • It’s own metadata
• A PDB CAN have :
  • a temporary tablespace or can use the CDB temporary tablespace.
  • it’s own Resource Manager Plan or can use the default CDB one.
• Users can be common users (at the CDB level) or local users (local to a PDB)

Continue reading OCP 12C – Basics of Multitenant Container Database (CDB) →