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書名： Oracle Data Guard 11gR2 Administration Beginner's Guide
作者名： Emre Baransel Nassyam Basha
本章字數： 355字
更新時間： 2021-08-13 17:12:25

Time for action – configuring standby redo logs on primary

Run the following procedures on the primary database to create standby redo logfiles:

Check the ORL's members and the sizes of each member as follows:

SQL> select a.group#, a.status, a.bytes/1024/1024 SizeMB, b.member from v$log a, v$logfile b where a.group#=b.group# order by group#;

GROUP# STATUS SizeMB MEMBER
------ -------- ---------- --------------------------------------
 1 INACTIVE 100 /u01/app/oracle/oradata/orcl/redo01.log
 2 CURRENT 100 /u01/app/oracle/oradata/orcl/redo02.log
 3 INACTIVE 100 /u01/app/oracle/oradata/orcl/redo03.log
 4 INACTIVE 100 /u01/app/oracle/oradata/orcl/redo04.log

Tip

In this single instance of the primary database, we have four redo log groups, each with one member and a size of 100 MB. We should create at least five standby redo log groups.

Add the standby redo logfiles as shown in the following example:

SQL> alter database add standby logfile group 11 ('/u01/app/oracle/oradata/orcl/standby_redo01.log') size 100m;
SQL> alter database add standby logfile group 12 ('/u01/app/oracle/oradata/orcl/standby_redo02.log') size 100m;
SQL> alter database add standby logfile group 13 ('/u01/app/oracle/oradata/orcl/standby_redo03.log') size 100m;
SQL> alter database add standby logfile group 14 ('/u01/app/oracle/oradata/orcl/standby_redo04.log') size 100m;
SQL> alter database add standby logfile group 15 ('/u01/app/oracle/oradata/orcl/standby_redo05.log') size 100m;

Check the status of new the standby redo logfiles:

SQL> select group#,bytes,status from v$standby_log;
GROUP# BYTES STATUS
------ --------- ----------
11 104857600 UNASSIGNED
12 104857600 UNASSIGNED
13 104857600 UNASSIGNED
14 104857600 UNASSIGNED
15 104857600 UNASSIGNED

What just happened?

We've completed the optional task of creating standby redo logs on the primary database. Again, if the standby redo logs were created on primary, the RMAN duplicate will create them on standby automatically.

Fast recovery area (FRA)

Prior to 11g R2, FRA stood for Flash Recover Area, but since Oracle Database 11g R2, FRA stands for Fast Recovery Area. It's a place on the disk where the database automatically manages naming, retention, and deletion of recovery-related files. FRA can contain control files, online redo logfiles, archived redo logs, flashback logs, and RMAN backups. It's not mandatory but strongly recommended to configure FRA.

In order to enable FRA, you need to set two initialization parameters and you don't need to shut down and restart the database. Note that, in Oracle RAC, these parameters should have the same values across instances and the location must be on shared storage.

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Oracle Data Guard 11gR2 Administration Beginner's Guide

Time for action – configuring standby redo logs on primary

Tip

What just happened?

Fast recovery area (FRA)