Oracle database High Availability – Exadata and Oracle 12c

November 1, 2013 by Leave a comment 

Going through different approaches in building Oracle database systems in best High Availability (HA) practices in my previous articles we went through following important topics:
understanding High Availability (HA) and SLA requirements; reviewing database Availability Levels based on industry standards; building High Availably (HA) database systems based on Oracle ASM, Clusterware and Cold Failover cluster; Oracle Data Guard, Standby and RAC; Extended RAC and MAA. Basically we finished everything but I wanted to give two more extras, which is Oracle Exadata and Oracle 12c High Availability features.

Oracle Exadata Database Machine

The integration of Oracle Maximum Availability Architecture (MAA) best practices with Oracle Exadata Database Machine (Exadata MAA) provides the most comprehensive Oracle High Availability (HA) solution available for the Oracle database. Exadata MAA is very matured and pre-optimized, pre-configured, integrated system of software, servers, storage and MAA configuration best practices that comes ready to implement the highest database High Availability.

Exadata MAA architecture shown in figure below is designed to tolerate unplanned outages of all types, providing both High Availability (HA) and data protection. Exadata MAA also minimizes planned downtime by performing maintenance in a rolling fashion.

Oracle Exadata MAA architecture

Oracle Exadata Maximum Availability Architecture (MAA) architecture

With Oracle Exadata X3 machine version 3 that was announced just before Oracle Open World 2012, Oracle extended the Exadata resources, features and the Support model that all improved the overall system High Availability (HA). The new Oracle Exadata X4 is going to be released in 2014.

See below some high-lights of Oracle Exadata X3
– Same architecture and price as X2

– 4x larger flash memory -> 22TB PCI flash memory per rack

– 20x more write performance -> Exadata Smart Flash Write Caching

– 33% more data throughput -> 100GB/sec running SQL

– 33% faster DB CPUs -> 8-Core Xeon SandyBridge E5-2690

– 75% more memory -> 2-4 TB DRAM

– Full 10Gb Ethernet to Data Centre

– 10-30% lower power -> Up to 3 Kilowatt Reduction per Rack

– New lower cost 1/8 rack solution

With new Exadata X3 Oracle introduced new Platinum Services that include the following

– Applied to Oracle Engineered Systems

– Delivered at no additional costs for Premier Support customers

– 24/7 oracle monitoring and remote diagnostics

– 5 Minute Fault Notification

– 15 Minute Restoration or Escalation to Development

– 30 Minute Joint Debugging with Development

– Quarterly system updates

Oracle Exadata Limitations

– Fairly expensive, especially in case you have to implement Oracle Exadata in both data Centres.

– You can not install other software on the Exadata machine apart what was delivered initially by Oracle

– You can not spread Exadata cluster nodes across 2 data centres or even server rooms

– Can not mirror storage across 2 locations

Oracle 12C High Availability (HA) features

Oracle has been hard at work for over three decades helping enterprises solve High Availability (HA) challenges by designing comprehensive HA capabilities integrated into the database. With the latest Oracle 12c database release Oracle introduced a considerable amount of features that increase High Availability of your database. I must admit though that many of the below listed are just extensions of old Oracle functionality with new names.

Oracle 12c Multitenant architecture

This is no more as the new Oracle database architecture is based on Container and Pluggable databases. Read more details in my articles about Oracle 12c Pluggable database feature.

Application Continuity

Application Continuity feature is an extension of Transparent Application Failover (TAF) in Oracle RAC database. In Oracle 12c it protects applications from database session failures due to instance, server, storage, network or any other related component. Application Continuity re-plays affected “in-flight” requests so that the failure of a RAC node appears to the application as a slightly delayed execution.

Global Data Services

Extends Database Services to span multiple Oracle 12c database instances in near and far locations. GDS extends RAC-like failover, service management, and service load balancing to replicated database configurations. GDS is intended for applications that are replication-aware.

Data Guard Fast & Far Sync

Extend zero-data-loss protection in Oracle 12c Data Guard environment

Flex ASM

Extension of Oracle ASM 12c by enabling inter-node storage failover and reducing ASM-related resource consumption.


These are new privileges to avoid granting SYSDBA

RMAN Enhancements

– Active Duplicate Cloning
– Oracle Secure Backup performance improvements
– Support for Multitenant architecture
– Table recovery from a backup
– Multi-section backup of image copies and incremental backups
– Direct support for SQL statements by the RMAN command line

More online operations

– Datafile move, partition move

OEM 12c Cloud Control

– Oracle Site Guard – extends automation of disaster recovery to the rest of the Oracle stack
– High Availability Console – integrates monitoring of various HA areas
– MAA Configuration Advisor
– Automation of migration a database to ASM and RAC

Database Rolling Upgrades using Active Data Guard

Choosing the correct High Availability architecture is not an easy task but can be accomplished based on High Availability (HA) best practices and recommendations, experts experience, business requirements and the available budget. As a summary with this article I covered two last extras that I wanted to share, which is Oracle Exadata and Oracle database 12c High Availability (HA) features.

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