Data Guard FAQ
(Doc ID 2930929.1)
Last updated on JULY 20, 2024
Applies to:
Oracle Database - Enterprise Edition - Version 11.2.0.1 and laterInformation in this document applies to any platform.
Purpose
This Document provides answers to "Frequently Asked Questions" in Data Guard environment.
When "standby" is used below, it is intended to refer to "physical standby".
Questions and Answers
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In this Document
| Purpose |
| Questions and Answers |
| 1. Data Guard Requirements and Environment Build |
| Q) Is it possible to use machines with different specs for the primary and standby databases ? |
| Q) Is it possible to create primary and standby databases on the same machine ? |
| Q) Is it possible to have different directory configurations on the primary and standby databases ? |
| Q) Can primary and standby databases be configured on different platforms ? |
| Q) Is it possible to use Data Guard with Oracle Database Standard Edition ? |
| Q) Are there any additional licenses required for using standby database ? |
| Q) Can primary or standby be used with Real Application Clusters (RAC) environment ? |
| Q) Is it possible to use Oracle Automatic Storage Management (ASM) on primary or standby ? |
| Q) What is the difference between the three types of standby databases (Physical standby, Logical standby, and Snapshot standby) ? |
| Q) Is it mandatory to create Standby Redo Logs ? |
| Q) Is it possible to create multiple standby databases for one primary database ? |
| Q) Is it possible to create a standby database of a standby database? |
| Q) What are the steps for applying PSR, PSU, RU, and PSE ? |
| Q) Is it possible to use Oracle Partitioning option on the primary only and not on the standby ? |
| Q) Is it possible to use different Oracle releases on the primary and standby databases ? |
| Q) Can primary and standby databases be permanently configured with different RUs ? |
| Q) What is Standby First Patch-Apply? |
| Q) How can user know if a patch supports Standby First Patch-Apply ? |
| Q) When applying a patch that supports Standby First Patch-Apply, is it possible to apply it to the primary database first ? |
| Q) What are the advantages and disadvantages of using the Data Guard Broker ? |
| Q) How can user check if the Data Guard Broker is being used ? |
| Q) Is it possible to configure Data Guard with Oracle Multitenant configuration ? |
| Q) Is it possible to synchronize data with Data Guard only for some PDBs in Multitenant configuration ? |
| 2. Operation and Management |
| Q) Is it possible to put noarchivelog mode at Data Guard environment? |
| Q) What should users do if users want to use the primary database separately from the standby database (i.e., without using Data Guard features) ? |
| Q) Is it possible to use backups of the standby database datafiles for recovery of the primary database ? |
| Q) Is it possible to use archivelog files from the standby database for recovery on the primary database ? |
| Q) What is the difference between failover and switchover? |
| Q) Is it necessary to recreate the standby database after recovery on the primary database ? |
| Q) When shutting down a database in Data Guard environment, which databases should be shutdown first ? |
| Q) What function should user use if user want to temporarily OPEN the physical standby in READ WRITE mode? |
| Q) Can Data Guard environment be monitored by DB Control or EM Express? |
| Q) Is it possible to monitor the Data Guard environment with Grid Control or Cloud Control? |
| Q) Is it possible to synchronize only some tables of the primary database with the standby database ? |
| Q) If NOLOGGING operations are performed on the primary database, what do user need on the standby database for recovery ? |
| Q) After adding datafiles on the primary database, is it necessary to do anything on the standby database ? |
| Q) If resizing the datafiles on the primary database, is there any work required on the standby database ? |
| Q) If changing the configuration of online REDO logs on the primary database, is it necessary to do anything on the standby database ? |
| Q) After renaming the datafiles on the primary database, is it necessary to do anything on the standby database ? |
| Q) Is it possible to change the datafile path on the standby database ? |
| Q) What should user do if the REDO logs path become unintended paths after the standby database is created ? |
| Q) What should user do if a datafile is added to an unintended path on the standby database after adding a datafile on the primary database ? |
| Q) Is it possible to create a new standby database from an already created standby database ? |
| Q) What are sample SQL statements that monitor the Data Guard environment ? |
| Q) Is it possible to generate AWR reports on the physical standby database ? |
| Q) Is it possible to obtain Active Session History on the standby database? |
| Q) Is it possible to generate Statspack reports on the standby database ? |
| Q) After changing initialization parameters on the primary database, will the changes be replicated to the standby database ? |
| Q) Is it mandatory to use recovery catalog when taking backups on the standby database with RMAN ? |
| Q) Is it possible to take online backups on the standby database? |
| Q) Is it possible to take consistent backups on the standby database ? |
| Q) Is it possible to perform export on the standby database ? |
| Q) How can user set up Data Guard configuration with the old primary database as the new standby database after performing failover ? |
| Q) Is it possible to execute DDL statements like create/drop tables/indexes and DML statements update rows on a physical standby database ? |
| Q) Is it possible to automatically change the standby database to the primary database if the primary database fails ? |
| Q) Is it possible to add new PDBs to a standby database in multitenant configuration ? |
| Q) Is it possible to perform Data Guard switchover/failover a single PDB ? |
| Q) Is it possible to create a new PDB or plug-in a new PDB to a primary database in multitenant configuration ? |
| Q) Why is a tempfile for temporary tablespace added on the primary database not added on the standby database ? |
| Q) There are no tempfiles in temporary tablespace on the standby database. What should user do ? |
| Q) How should user recreate password file ? |
| Q) Is it possible to refer to DBA and V$ views on the standby database ? |
| Q) Should datapatch or scripts be run on both primary and standby databases when applying patches ? |
| 3. Log Apply |
| Q) Is it possible to apply archivelog files generated on the primary database to the standby database ? |
| Q) Is it possible to execute log apply in parallel ? |
| Q) Is it possible to execute log apply serially ? |
| Q) If the standby database is in RAC configuration, on which node will log apply execute ? Also, how can user check which node is log apply running ? |
| Q) Is it possible to have a wait time before applying logs to the standby database ? |
| Q) If user want to manually apply archivelog files by executing a command, what is the method ? |
| Q) How can user check if archivelog files have been applied ? |
| Q) Archivelog files exist but are not applied. What should user do ? |
| Q) Will REDO Apply automatically start after standby database startup ? |
| 4. Log Transport |
| Q) Is it possible to temporarily stop log transport to the standby database ? |
| Q) Is it possible to specify a specific time to transport logs to standby ? |
| Q) Is there a way to automatically generate a log switch at regular intervals ? |
| Q) If the network between primary and standby is slow, what transport mode should user select ? |
| Q) If log transport fails with any errors, will it automatically resume ? |
| Q) If log transport fails with any errors, can the transfer be restarted immediately? |
| Q) The standby database has not been running for a certain period of time and has not been able to transfer redo data from the primary database. Is there anything that needs to be done in this case? |
| Q) Is it possible to transfer redo data to cascaded standby in real time ? |
| Q) If user stop the standby database, should user stop log transport ? |
| Q) If log transport to the standby database is delayed, will it affect the performance of the primary database ? |
| References |