如何搭建RMAN备份平台-mysql教程

Suppose you set PARALLELISM for disk backups to 2 (see ). If you set the default device type as disk, then RMAN allocates two disk channels when you run BACKUP DATABASE at the RMAN prompt. RMAN always allocates the number of channels set by PARALLELISM, although it may use only a subset of these channels.

Note: If you configure n manually numbered channels, then the PARALLELISM setting can be greater than or less than n. For example, you can manually number 10 automatic channels and configure PARALLELISM to 2 or 12.

To change the parallelism for a device type to n, run a new CONFIGURE DEVICE TYPE ... PARALLELISM n command. For example, you can change configure PARALLELISM to 3 for sbt and then change it to 2 as follows:

.com/docs/cd/E11882_01/backup.112/e10643/rcmsynta010.htm#RCMRF113

2.2 修改控制文件保存的时间

否则就可能在备份介质上有数据库备份，但是控制文件不存在与备份相关的备份记录，，在这种情况下，将无法恢复这些较早的文件。

SQL> select name,value from v$parameter where name='control_file_record_keep_time';

NAME VALUE

------------------------------ -------------------------------------------------

control_file_record_keep_time 7

SQL> alter system set control_file_record_keep_time=20;

系统已更改。

SQL> show parameter control_file_record_keep_time

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

control_file_record_keep_time integer 20

2.3 配置备份默认的保存策略

备份策略影响影响恢复，如果备份集少，那么恢复能力也受到限制，如果备份集留的比较多，那么也会占用大量的空间。 所以要设置一个合适的周期，这个要根据磁盘空间大小和恢复需要来设置，一般有2种方法：

2.3.1 通过recovery window

如：configure retention policy to recovery window of 7 days;

2.3.2 通过redundancy

如：configure retention policy to redundancy 5;

它的默认值是1份。

report obsolete;

delete noprompt obsolete;

crosscheck backup;

delete noprompt expired backup;

configure retention policy clear;

2.3.4 不应用任何保存策略。

CONFIGURE RETENTION POLICY TO NONE;

2.4 部署备份脚本

参考blog：

2.5 删除归档日志的脚本

小结，对于DBA来说，完整有效的备份是非常重要的，它能在关键时刻恢复我们的数据，或者减少数据丢失，所以对于生产库，一定要做好备份策略。 备份重于一切！