如何理解DRA特性

如何理解DRA特性，很多新手對此不是很清楚，為了幫助大家解決這個難題，下面小編將為大家詳細講解，有這方面需求的人可以來學(xué)習(xí)下，希望你能有所收獲。

DRA在遇到錯誤時會自動收集數(shù)據(jù)故障信息。此外，它還能預(yù)先檢查故障。在此模式中，它可以在數(shù)據(jù)庫進程發(fā)現(xiàn)損壞并發(fā)送錯誤消息之前檢測和分析數(shù)據(jù)故障。
DRA的優(yōu)勢：
? Data Recovery Advisor can potentially detect, analyze, and repair data failures before a database process discovers the corruption and signals an error. Early warnings help limit damage caused by corruption.DRA可以覺察，分析，修復(fù)數(shù)據(jù)庫錯誤
? Manually assessing symptoms of data failures and correlating them into a problem statement can be complex, error-prone, and time-consuming. Data Recovery Advisor automatically diagnoses failures, assesses their impact, and reports these findings to the user.
? Traditionally, users must manually determine repair options along with the repair impact. If multiple failures are present, then users must determine the right sequence of repair execution and try to consolidate repairs. In contrast, Data Recovery Advisor automatically determines the best repair options and runs checks to make sure that these options are feasible in your environment.
? Execution of a data repair can be complex and error-prone. If you choose an automated repair option, then Data Recovery Advisor executes the repair and verifies its success.
rman中包括以下命令都屬于DRA特性
LIST FAILURE, ADVISE FAILURE, REPAIR FAILURE, and CHANGE FAILURE.


list failure 可以查看操作錯誤和造成的影響
advice failure查看修復(fù)的選項，一般都包含自動和手動
repair failure 在advice failure之后可以使用repaire failure修復(fù)錯誤


手動修改了user01.dbf文件
RMAN> list failure;


no failures found that match specification
沒有發(fā)現(xiàn)錯誤
sqlplus連接數(shù)據(jù)庫，查詢表
SQL> select * from scott.emp;
select * from scott.emp
                    *
ERROR at line 1:
ORA-01116: error in opening database file 4
ORA-01110: data file 4: '/u01/app/oracle/oradata/test/users01.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
再次list failure
RMAN> list failure;


List of Database Failures
=========================


Failure ID Priority Status    Time Detected       Summary
---------- -------- --------- ------------------- -------
42         HIGH     OPEN      2017-07-30 19:54:08 One or more non-system datafiles are missing
一個或多個非系統(tǒng)數(shù)據(jù)文件丟失


RMAN> advise failure;


List of Database Failures
=========================


Failure ID Priority Status    Time Detected       Summary
---------- -------- --------- ------------------- -------
42         HIGH     OPEN      2017-07-30 19:54:08 One or more non-system datafiles are missing


analyzing automatic repair options; this may take some time
using channel ORA_DISK_1
analyzing automatic repair options complete


Mandatory Manual Actions
========================
1. If file /u01/app/oracle/oradata/test/users01.dbf was unintentionally renamed or moved, restore it
2. If you have an export of tablespace USERS, then drop and re-create the tablespace and import the data.
3. Contact Oracle Support Services if the preceding recommendations cannot be used, or if they do not fix the failures selected for repair


Optional Manual Actions
=======================
no manual actions available


Automated Repair Options
========================
no automatic repair options available
沒有自動修復(fù)選項

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