Tuesday Apr 22, 2014

HA Best Practices for Database Consolidation

Read this new white paper to learn how to deploy and optimize Database-as-a-Service using Oracle Multitenant and Oracle MAA.

Wednesday Apr 10, 2013

Exadata Maximum Availability Tests

Recently Oracle published the below video created by our group (MAA  team) which demonstrates Exadata's High Availability in the face of hardware and software failures.  This video is a great showcase on how Exadata handles hardware and software failures. These are tests Oracle does on a daily basis for Engineered systems so every Exadata customer benefits  !

Exadata Maximum Availability Tests from ESG Media on Vimeo.

Thursday Oct 25, 2012

Demo on Data Guard Protection From Lost-Write Corruption

Today I received the news a new demo has been made available on OTN for Data Guard protection from lost-write corruption. Since this is a typical MAA solution and a very nice demo I decided to mention this great feature also in this blog even while it's a recommended best practice for some time.

When lost writes occur an I/O subsystem acknowledges the completion of the block write even though the write I/O did not occur in the persistent storage. On a subsequent block read on the primary database, the I/O subsystem returns the stale version of the data block, which might be used to update other blocks of the database, thereby corrupting it.  Lost writes can occur after an OS or storage device driver failure, faulty host bus adapters, disk controller failures and volume manager errors.

In the demo a data block lost write occurs when an I/O subsystem acknowledges the completion of the block write, while in fact the write did not occur in the persistent storage. When a primary database lost write corruption is detected by a Data Guard physical standby database, Redo Apply (MRP) will stop and the standby will signal an ORA-752 error to explicitly indicate a primary lost write has occurred (preventing corruption from spreading to the standby database).


  • MOS (1302539.1). "Best Practices for Corruption Detection, Prevention, and Automatic Repair - in a Data Guard Configuration"
  • Demo
  • MAA Best Practices

Rene Kundersma

Friday Sep 09, 2011

Software Updates, Best Practices and Notes

With a very busy time behind and ahead of me, I still like to make mention of a couple of documents recently we published.

OPlan is now available for Linux as well as Solaris X86-64 for the Oracle Exadata Database Machine. The current version of OPlan is For more details, see my previous post

The two notes mentioned below explain about how OPlan can be used and demo how OPLan works to clone the Grid Infrastructure on the Database Machine, patch the cloned home and switch to it. This is called out-of-place patching.

  • MOS Note 1306814.1 - Oracle Software Patching with OPLAN
  • MOS Note 1136544.1 - Minimal downtime patching via cloning 11gR2 ORACLE_HOME directories

Supported software versions for Exadata are still listed in MOS note 888828.1, this is where you will find a reference to the latest Exadata Storage Server software release:, available via patch 12849110. Please see note 1334254.1 for the details.

For the Database Server, the latest patch made available for is Bundle Patch 10, available via Patch 12773458 (Linux version). Please know that BP's can be applied by EM, which makes patching more easy.

For ASR we now have release version 3.3 Released. Details can be found in Note 1185493.1.
The latest PDU metering unit firmware is 1.04 and available as patch 12871297.

For MAA Best pracitces releated to the database machine we released a real good document called "Oracle Exadata Database Machine Consolidation: Segregating Databases and Roles", which you can find here

Also releated to best practices is the document "MAA Best Practices for Oracle Exadata Database Machine", you can find that here

Rene Kundersma

Tuesday May 24, 2011

New papers: DR for Exalogic and Exadata + Oracle GoldenGate on Exadata

Recently an updated version of to the MAA whitepaper "Oracle GoldenGate on Oracle Exadata Database Machine Configuration" has been made available. With this update new information is added regarding:

  • DBFS performance configuration
  • Details of DBFS configuration for node failover
  • GoldenGate Replicat commit behavior configuration
  • The agent failover script for clean start-up of GoldenGate

Also a new document is published called "Disaster Recovery for Oracle Exalogic Elastic Cloud with Oracle Exadata Database Machine". This document discusses :

  • Oracle Fusion Middleware Disaster Recovery architecture and strategy for deployments on Oracle Exalogic with Oracle Exadata Database Machine
  • Detailed deployment and configuration steps for the Oracle Fusion Middleware Disaster Recovery solution on Oracle Exalogic and Oracle Exadata Database Machine.
  • Best practices for the Oracle Fusion Middleware Disaster Recovery solution with Exalogic and Exadata
Rene Kundersma

Thursday May 19, 2011

exachk: healtcheck for Exadata

With this entry I like to handle exachk. Exachk is made available via MOS Doc Id. 1070954.1. The tool is designed to audit various important configuration settings
within an Oracle Database Machine Exadata System - Database Servers, Storage Servers and Infiniband Switches. It verifies key components of the Exadata Database Machine against supported version levels, recommended Oracle RAC settings and Exadata best practices. At the moment we support version 11gR2 for V2 & X2-2.

The tool is non-intrusive, when it completes it's collection and analysis it produces two reports, summary and detailed. If an SR needs to be logged the output can be supplied to Oracle for further analysis . The detailed report will contain Benefit/Impact, Risk and Action/Repair information. In many cases it will also reference publicly available documents with additional information about best practices and how to implement them.

For more and detailed information please see MOS Doc Id. 1070954.1

Rene Kundersma


Blog of Rene Kundersma, Principal Member of Technical Staff at Oracle Development USA. I am designing and evaluating solutions and best practices around database MAA focused on Exadata. This involves HA, backup/recovery, migration and database consolidation and upgrades on Exadata. Opinions are my own and not necessarily those of Oracle Corporation. See http://www.oracle.com/technology/deploy/availability/htdocs/maa.htm.


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