rman备份策略制定参考内容(二)

You plan to use Flashback Database or a guaranteed restore point as alternatives to point-in-time recovery in response to logical errors

If you plan to enable flashback logging, then the volume of flashback log generation is approximately the same order of magnitude as redo log generation. For example, if you intend to set DB_FLASHBACK_RETENTION_TARGETto 24 hours, and if the database generates 20 gigabytes of redo in a day, then a general rule of thumb is to allow 20 GB to 30 GB of disk space for the flashback logs. The same rule applies to guaranteed restore points when flashback logging is enabled. For example, if the database generates 20 GB of redo every day, and if the guaranteed restore point is kept for a day, then plan to allocate 20 to 30 GB.

Suppose that you want to determine the size of a fast recovery area when the backup retention policy is set toREDUNDANCY 1 and you intend to follow Oracle's suggested strategy of using an incrementally updated backup. In this example, you use the following formula to estimate the disk quota, where n is the interval in days between incremental updates and y is the delay in applying the foreign archived redo logs on a logical standby database:

Disk Quota =
Size of a copy of database +
Size of an incremental backup +
Size of (n+1) days of archived redo logs +
Size of (y+1) days of foreign archived redo logs (for logical standby) +
Size of control file +
Size of an online redo log member * number of log groups +
Size of flashback logs (based on DB_FLASHBACK_RETENTION_TARGET value)

看起太复杂了 。我采用的方法是 先大楷估计oracle的数据量，合理分配一个大小。以后每天检查一次快速恢复区的大小；

SELECT * FROM V$RECOVERY_FILE_DEST; 查看快速恢复区大小

SELECT * FROM V$RECOVERY_AREA_USAGE; 查看有那些文件

在根据备份策略来合理的进行设置大小！

如：我现在的备份策略是 基于时间窗口30天的备份策略。周末0级增备，1,2,3差异增备，4累计增备，5，6差异增备！

没开闪回 数据库，归档日志在其他目录下，redo也没在快速恢复区中。

每天数据量改变不到5%。刚才我做了个全备，占用了1.5G快速恢复区大小。根据rman策略，设置大小为：10G大小。