36 Overview of Oracle Multitenant Best Practices
Oracle Multitenant is Oracle's strategic product for database consolidation.
The benefits of the Oracle Multitenant architecture include:
- Access isolation between individual Pluggable Databases (PDBs) stored in the same Container Database (CDB)
- Ability to manage many databases with the simplicity of managing just one CDB that contains many PDBs. By backing up your CDB, updating the CDB software or setting up a standby CDB for disaster recovery, you are essentially reducing the complexity and steps by administrating one CDB instead of applying the same administrative steps on many independent databases. You reduce administrative tasks, steps and errors.
- Sharing of system resources to reduce CAPEX with the flexibility to set resource limits for things like memory, I/O and on a per PDB level
- Flexibility to operate on an individual PDB, for example relocating a single PDB into another container and upgrading just that PDB
- Rapid cloning and provisioning
- Tight integration with Oracle RAC
The following table highlights various Oracle Multitenant configuration and operational best practices.
Table 36-1 Oracle Multitenant configuration and operational best practices
Use Case | Best Practices |
---|---|
Pluggable Database (PDB) configuration |
For all Oracle RDBMS releases 12c Release 2 (12.2) to 21c, configure the CDB with local undo mode See Undo Modes in 12.2 Multitenant Databases - Local and Shared Modes (Doc ID 2169828.1) |
PDB service management |
Mandatory MAA best practices for any Oracle databases with Oracle Clusterware (for example, Oracle RAC and single instance databases with Oracle Clusterware installed)
If the above practices are applied, you will have predictable service management during PDB open and Data Guard role transitions. This will lead to higher application service availability and avoid application errors. For single instance databases without MAA-recommended Oracle clusterware setup, follow these practices:
|
Using Data Guard with Oracle Multitenant |
The following My Oracle Support notes provide operational best practice recommendations when using Oracle Multitenant in an Oracle Data Guard configuration.
|
Data Guard: PDB switchover and failover use cases |
|
PDB migration |
The following My Oracle Support notes provide operational best practices for different types of PDB migration with minimal downtime:
|
PDB relocation |
|
PDB resource management |
The following My Oracle Support note provides operational use cases for Oracle Multitenant resource management: |
With Oracle Multitenant MAA solutions, you can achieve administration and system resource savings while still benefiting from various MAA solutions. The following tables highlight zero and near-zero downtime and data loss for various unplanned outages and planned maintenance activities.
Table 36-2 Unplanned Outages
Unplanned Outages | Key Features for Solution | RTO | RPO |
---|---|---|---|
Recoverable node or instance failures |
Real Application Cluster (RAC) Application Continuity (AC) |
Seconds | Zero |
Database, cluster, and site failures |
Active Data Guard fast-start failover |
<2 Minutes | Zero or Seconds |
Data corruptions |
Active Data Guard that includes auto block repair of physical corruptions |
Zero | Zero |
PDB unrecoverable failure or "sick" PDB |
PDB failover using Data Guard migrate command Another target CDB on the same cluster is required |
<2 Minutes | Zero or Seconds |
PDB failover to active replica |
Option 1: Failover entire CDB with Primary and Standby CDB Data Guard architecture Option 2: Create PDB replica with Oracle GoldenGate. Perform PDB active failover using PDB replica in a different CDB. Use Global Data Services and practices from Application Checklist for Continuous Service for MAA Solutions help with the application failover |
Potentially Zero | Zero or Seconds |
Table 36-3 Planned Maintenance
Planned Downtime | Solution | RTO |
---|---|---|
Software and hardware updates |
Real Application Cluster (RAC) Application Checklist for Continuous Service for MAA Solutions |
Zero |
Major database upgrade for entire CDB |
Active Data Guard DBMS_ROLLING |
Seconds |
Major database upgrade for single PDB within CDB |
PDB Relocate + Upgrade See Using PDB Relocation to Upgrade an Individual PDB (Doc ID 2771716.1) |
Minutes |
Migration to remote CDB |
PDB Relocate See Using PDB Relocation to Move a Single PDB to Another CDB Without Upgrade (Doc ID 2771737.1) |
Minutes |
Migration to remote CDB (logical migration) |
Data Pump and Oracle GoldenGate or Zero Downtime Migration |
Potentially Zero |