Data Guard Protection from Lost-Write Corruption

En esta demo de la serie High Availability Demonstrations podemos ver cómo Data Guard proporciona una protección única contra la corrupción de datos causada por escrituras perdidas ("Lost Writes"). Una escritura perdida de bloque de datos ocurre cuando un subsistema de E/S entiende que la escritura del bloque ya ha finalizado, mientras que de hecho esto no ha ocurrido realmente en el storage. Cuando se detecta una corrupción del tipo "Lost Write" en una base de datos física Standby de Data Guard, el proceso Redo Apply (MRP) se detendrá y la standby mostrará un error ORA-752 para indicar explícitamente que se ha producido un error de "Lost Write" en la primaria. (Esto lo hace para prevenir que el problema se propague a la standby). Para obtener más información sobre "Lost Write Protection" y comocer sobre otras formas de como Oracle Data Guard puede prevenir, detectar o reparar automáticamente corrupción de datos, consulte la nota de MOS 1302539.1

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Preventing, Detecting, and Repairing Block Corruption: Oracle Database 12c (White Paper)

Preventing, Detecting, and Repairing Block Corruption: Oracle Database 12c

Oracle Maximum Availability Architecture

Oracle White Paper 

Executive Overview

In today’s information-driven enterprises, business critical information must be highly available, from internal company-sensitive data to applications that manage crucial partner and customer relationships. Outages are costly in lost revenue and damaged reputation, and can be crippling to the business.

Block corruptions are a common source of database outages. A database block is corrupted when its content has changed from what Oracle Database expects to find. If not prevented or repaired, block corruption can bring down the database and possibly result in the loss of key business data.

This Oracle Maximum Availability Architecture (MAA) white paper presents the essential tools, techniques, and best practices to help you safeguard data and prevent corruptionrelated database outages. MAA is Oracle’s comprehensive best practices blueprint for implementing Oracle high availability technologies. The MAA best practices are described in a series of technical white papers and documentation to assist in designing, implementing, and managing optimal high availability architectures. The series of MAA white papers are available at the Oracle Maximum Availability Architecture website.

This paper is applicable to Oracle Database 12c and Oracle Database 11g Release 2.

http://www.oracle.com/technetwork/database/availability/corruption-bestpractices-12c-2141348.pdf