How to create standby redo logs in oracle 12c

Last Updated: May 11, 2021 | Author: Paul-Bilodeau

How do I recreate standby redo logs in Oracle 12c?

In this case you have to just shutdown the database, bring it to mount stage and drop the standby redo log group. On Primary database -> SQL>alter system switch logfile; On Standby Database –> Check if it is moved other group.

How do you create a standby redo log on a standby database?

To create new standby redo log file groups and members, you must have the ALTER DATABASE system privilege. The standby database begins using the newly created standby redo data the next time there is a log switch on the primary database.

How do I create a standby redo log in Oracle 12c ASM?

Configure a Standby Redo Log, SQL> alter database add standby logfile group 3 size 150m; Database altered. SQL>alter database add standby logfile group 4 size 150m Database altered. SQL>alter database add standby logfile group 5 size 150m Database altered.

What is standby redo log file in Oracle?

Answer: A standby redo log resides on the standby database site. The standby redo log file is similar to an online redo log, except that a standby redo log is used to store redo data that has been received from a primary database. Oracle Data Guard used to have the onerous problem of loosing the last redo log.

How do I check standby for redo logs?

How to identify standby redo logs ? SQL> select * from v$logfile where type=’STANDBY‘; .

Why do we need standby redo logs?

If you configure your standby for Maximum Protection, then Standby Redo Logs are required. Because a standby database exists, a second Archiver process (ARC1) will read from a completed Archived Redo Log and transmit the redo over the network to the Remote File Server (RFS) process running for the standby instance.

How many standby redo logs needed?

The standby redo log must have at least one more redo log group than the redo log at the redo source database. Standby redolog is mandatory for realtime apply. In 12c DEFAULT MRP will go to REAL TIME APPLY mode. Oracle recommends to keep standby redologs on both primary and standby database.

What is online redo log files?

The most crucial structure for recovery operations is the online redo log, which consists of two or more preallocated files that store all changes made to the database as they occur. Every instance of an Oracle database has an associated online redo log to protect the database in case of an instance failure.

What is written in redo log files?

Redo Logs consist of two or more pre-allocated files that store all changes made to the database as they occur. Redo entries record data that you can use to reconstruct all changes made to the database, including the undo segments. Therefore, the redo log also protects rollback data.

What is difference between archive and redo log?

Archive logs are archived redo(online) log files. In redo log files are all changes that happened to your data. If your database is in archivelog mode, than redo logs can’t be overwritten, they are archived in some other location when they are full. Redo and archive logs are used in various database recovery scenarios.

What are the archived redo logs used for?

Archived redo logs are integral to maintaining a standby database, which is an exact replica of a database. You can operate your database in standby archiving mode, which automatically updates a standby database with archived redo logs from the original database.

How do I manually use redo logs?

To apply the archived redo logs in the archive gap

Start up and mount the standby database (if it is not already mounted). For example, enter: SQL> STARTUP NOMOUNT PFILE=/oracle/admin/pfile/initSTBY.

Where are redo logs?

Redo log files are used to record data changes to the database. The redo log files are initially specified within the CREATE DATABASE command. CREATE DATABASE . . . LOGFILE ‘/t02/oradata/MYDB/redo1.

How do I know if archive logs are applied to standby database?

Another check to verify that primary and standby are in sync: Run the following query on both standby and primary after all logs in v$archived_log show APPLIED=YES: SQL> select max(sequence#) from v$log_history. Output should be same on both databases.

How do I check if standby is enabled?

On the primary database, check the last sequence that is generated. SQL> select max(sequence#) from V$archived_log; 4. On the standby database, check the last sequence that is applied.

Using DGbrocker.

  1. Set proper ORACLE_SID, ORACLE_HOME.
  2. dgmgrl.
  3. connect /
  4. show configuration;
  5. show database ‘DB name’;

How do I manually apply archive logs to standby database?

  1. Create a backup (hot or cold) of the Primary database datafiles.
  2. Create a standby controlfile on the primary. SVRMGR> alter database create standby controlfile as.
  3. Copy the datafiles, standby controlfile, and configuration files from the.
  4. Edit the Primary “init.ora” file.
  5. Edit the Standby “init.ora” file.

How do I break standby database?

Then, on both primary and standby, bring up in OPEN mode and disable further replication: SQL> ALTER DATABASE OPEN; SQL> ALTER SYSTEM SET LOG_ARCHIVE_DEST_2=”; I have 3 problems/questions with this approach: As a general statement, this feels a little overly complex – is there a more direct way to do this?

How do I start MRP in standby?

8.1. 1 Starting Up a Physical Standby Database
  1. Start and mount the physical standby database: SQL> STARTUP MOUNT;
  2. Start Redo Apply or real-time apply: To start Redo Apply, issue the following statement: SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE 2> DISCONNECT FROM SESSION;

How do I start an active standby database?

Steps to Enable Active Data Guard Option
  1. Cancel The Redo Apply Process. SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
  2. Shutdown and start the database in Mount Mode.
  3. Open the database in Read-Only Mode.
  4. Start the Redo Apply. (
  5. Now that the standby is in real-time query mode (the standby is open in read-only.

How do I connect to a standby database?

We need to connect with the connect string: “justinb/PWD@DBNAME as sysdba”. The latter connect string allows you to authenticate using the Oracle password file, which you have to use with a standby because the database is mounted, not opened.

How do I know if my database is primary or standby?

You can use the DGMGRL show configuration and show database database_name commands to confirm the Data Guard Standby database configuration before enabling a standby database. Here is how you enable your primary and standby databases using the DGMGRL command: DGMGRL> enable configuration; Enabled.

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