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RAC 之 RMAN 备份

發(fā)布時(shí)間：2023/12/20 编程问答 30 豆豆

生活随笔收集整理的這篇文章主要介紹了 RAC 之 RMAN 备份小編覺得挺不錯(cuò)的,現(xiàn)在分享給大家,幫大家做個(gè)參考.

這篇主要介紹的是RAC 環(huán)境下的RMAN 備份。關(guān)于Oracle 備份與恢復(fù)的一些理論知識(shí)參考我的Blog：

????? Oracle 備份與恢復(fù) 概述

?????? http://blog.csdn.net/tianlesoftware/archive/2010/04/16/5490733.aspx

一．???? RAC 歸檔的設(shè)置

1.1? 相關(guān)理論知識(shí)

RAC 在運(yùn)行的時(shí)候，每個(gè)實(shí)例都會(huì)產(chǎn)生歸檔日志，所有實(shí)例的歸檔日志集中在一起，才能完整地代表數(shù)據(jù)庫的操作歷史，此外，只有進(jìn)行介質(zhì)恢復(fù)（Media Recovery）時(shí)，才會(huì)用到歸檔日志。進(jìn)行介質(zhì)恢復(fù)時(shí)，才要求在執(zhí)行恢復(fù)操作的那個(gè)節(jié)點(diǎn)訪問所有實(shí)例的歸檔日志。

正是因?yàn)闅w檔日志有這些特點(diǎn)，所以歸檔位置的設(shè)計(jì)也有兩種方案：

（1）各節(jié)點(diǎn)生成的歸檔放到共享存儲(chǔ)上，這樣自然可以確保每個(gè)節(jié)點(diǎn)都能夠訪問到，比如將歸檔存放到ORACLE的ASM，或者是第三方提供的集群文件系統(tǒng)中。對于這種方法，一些集群的配置比較麻煩，而且也增加了ASM的維護(hù)，出現(xiàn)問題也不好處理。

（2）各節(jié)點(diǎn)除在本地生成歸檔文件外，另外向其它節(jié)點(diǎn)或者說執(zhí)行備份的節(jié)點(diǎn)發(fā)送歸檔日志，以確保執(zhí)行備份的那臺(tái)節(jié)點(diǎn)能夠訪問到所有的歸檔文件。在這種方法中，因?yàn)?/span>ORACLE 的重做日志發(fā)送機(jī)制非常靈活，在10g版本中可以同時(shí)向10個(gè)目標(biāo)地寫入歸檔(11g增加到了30個(gè))，所以利用這種特性，將各節(jié)點(diǎn)生成的歸檔發(fā)送到執(zhí)行備份的節(jié)點(diǎn)中，來實(shí)現(xiàn)該節(jié)點(diǎn)能夠訪問所需的歸檔文件。

在第二種方案中，我們可以在每個(gè)節(jié)點(diǎn)建2個(gè)歸檔目錄,分別存放本地和其他節(jié)點(diǎn)節(jié)點(diǎn)的歸檔日志，這里假設(shè)是2個(gè)節(jié)點(diǎn)的RAC.

歸檔位置	實(shí)例1	實(shí)例2
本地磁盤	Mkdir /rac1_arch Mkdir /rac2_arch	Mkdir /rac1_arch Mkdir /rac2_arch
Log_archive_dest_1	Location=’/rac1_arch’	Location=’/rac2_arch’
Log_archive_dest_2	Service=’rac2’	Service=’rac1’
Standby_archive_dest	‘/rac2_arch’	‘/rac1_arch’

在每個(gè)節(jié)點(diǎn)上建2個(gè)目錄: /u02/rac1_arch, /u02/rac2_arch，并賦予讀寫的權(quán)限：

[root@rac2 /]# mkdir /u02/rac1_arch

[root@rac2 /]# mkdir /u02/rac2_arch

[root@rac2 /]# chown oracle:oinstall /u02/*

[root@rac2 /]# chmod 777 /u02/*

??????

1.2 ?RAC 設(shè)置成歸檔模式

?????? RAC的歸檔設(shè)置和單實(shí)例歸檔設(shè)置差不多。先將所有實(shí)例設(shè)置為非OPEN狀態(tài)，然后在任意一個(gè)處于MOUNT狀態(tài)的實(shí)例執(zhí)行ALTER DATABASE命令，操作成功后，再正常啟動(dòng)其它實(shí)例即可。

之前整理的一篇RAC 歸檔切換的文檔，不過和今天這個(gè)實(shí)驗(yàn)不太匹配，就重新在整理下。

Oracle RAC 歸檔與非歸檔切換

http://blog.csdn.net/tianlesoftware/archive/2010/04/20/5501184.aspx

1.2.1 設(shè)置歸檔參數(shù)

1.2.1.1 設(shè)置實(shí)例orcl1的參數(shù)：

SQL> alter system set log_archive_dest_1 = 'LOCATION=/u02/rac1_arch' scope=both sid='orcl1';

System altered.

SQL> alter system set log_archive_dest_2 = 'service=orcl2' scope=both sid='orcl1';

System altered.

SQL> alter system set standby_archive_dest = '/u02/rac2_arch' scope=both sid='orcl1';

System altered.

1.2.1.2 設(shè)置實(shí)例orcl2的參數(shù)：

SQL> alter system set log_archive_dest_1 = 'LOCATION=/u02/rac2_arch' scope=both sid='orcl2';

System altered.

SQL> alter system set log_archive_dest_2= 'SERVICE=orcl1' scope=both sid='orcl2';

System altered.

SQL> alter system set standby_archive_dest = '/u02/rac1_arch' scope=both sid='orcl2';

System altered.

1.2.1.3 在2個(gè)節(jié)點(diǎn)上分別驗(yàn)證參數(shù)的狀態(tài)：

SQL> set wrap off

SQL> col dest_name format a20

SQL> select dest_name,status,error from v$archive_dest;

DEST_NAME??????????? STATUS??? ERROR

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

LOG_ARCHIVE_DEST_1?? VALID

LOG_ARCHIVE_DEST_2?? VALID

LOG_ARCHIVE_DEST_3?? INACTIVE

LOG_ARCHIVE_DEST_4?? INACTIVE

LOG_ARCHIVE_DEST_5?? INACTIVE

LOG_ARCHIVE_DEST_6?? INACTIVE

LOG_ARCHIVE_DEST_7?? INACTIVE

LOG_ARCHIVE_DEST_8?? INACTIVE

LOG_ARCHIVE_DEST_9?? INACTIVE

LOG_ARCHIVE_DEST_10? INACTIVE

10 rows selected.

1.2.2 將RAC 切換成歸檔模式

1.2.2.1 修改數(shù)據(jù)庫的歸檔模式

?????? SQL> alter system set cluster_database=false scope=spfile sid='*';

System altered.

1.2.2.2 關(guān)閉所有實(shí)例

?????? SQL> shutdown immediate

1.2.2.3 在任意一個(gè)實(shí)例上將數(shù)據(jù)庫啟動(dòng)到mount狀態(tài)，修改數(shù)據(jù)庫歸檔模式

SQL> startup mount

ORACLE instance started.

Total System Global Area? 167772160 bytes

Fixed Size????????????????? 1266392 bytes

Variable Size???????????? 117443880 bytes

Database Buffers?????????? 46137344 bytes

Redo Buffers??????????????? 2924544 bytes

Database mounted.

SQL> alter database archivelog;

Database altered.

SQL> alter system set cluster_database=true scope=spfile sid='*';

System altered.

?????? ? SQL> shutdown immediate

1.2.2.4 重啟數(shù)據(jù)庫，確定歸檔生效

SQL> archive log list;

Database log mode????????????? Archive Mode

Automatic archival???????????? Enabled

Archive destination??????????? /u02/rac1_arch

Oldest online log sequence???? 54

Next log sequence to archive?? 55

Current log sequence? ?????????55

SQL> archive log list;

Database log mode????????????? Archive Mode

Automatic archival???????????? Enabled

Archive destination??????????? /u02/rac2_arch

Oldest online log sequence???? 26

Next log sequence to archive?? 27

Current log sequence?? ????????27

1.2.2.5 在兩個(gè)節(jié)點(diǎn)分別切換歸檔日志，并檢查對應(yīng)的目錄是否產(chǎn)生歸檔日志

?????? SQL> alter system switch logfile;

System altered.

SQL> select inst_id,recid,dest_id,name from gv$archived_log ;

? INST_ID????? RECID??? DEST_ID NAME

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

???????? 2???????? 12????????? 1 /u02/rac1_arch/1_5_730181171.dbf

???????? 2???????? 13????????? 2 /u01/rac1_arch1_5_730181171.dbf

???????? 2???????? 14????????? 2 /u02/rac2_arch/2_3_730181171.dbf

???????? 2???????? 15????????? 1 /u02/rac1_arch/1_6_730181171.dbf

???????? 2???????? 16????????? 2 /u02/rac1_arch/1_6_730181171.dbf

???????? 2???????? 17????????? 1 /u02/rac1_arch/1_7_730181171.dbf

????????????? ……

???? ????1???????? 12????????? 1 /u02/rac1_arch/1_5_730181171.dbf

???????? 1???????? 13????????? 2 /u01/rac1_arch1_5_730181171.dbf

???????? 1???????? 14????????? 2 /u02/rac2_arch/2_3_730181171.dbf

???????? 1???????? 15????????? 1 /u02/rac1_arch/1_6_730181171.dbf

???????? 1???????? 16????????? 2 /u02/rac1_arch/1_6_730181171.dbf

提示：RAC 數(shù)據(jù)庫各實(shí)例擁有各自的REDO線程，歸檔文件名的生成規(guī)則由LOG_ARCHIVE_FORMAT初始化參數(shù)控制，默認(rèn)情況下是 %t_%s_%r.dbf ，所以不會(huì)導(dǎo)致重復(fù)的發(fā)生。

注意一個(gè)參數(shù)：LOG_ARCHIVE_LOCAL_FIRST，用來設(shè)置是否首先歸檔文件到本地，默認(rèn)為true.

LOG_ARCHIVE_LOCAL_FIRST 這個(gè)參數(shù)是Oracle 10g 新增的，它主要針對Standby環(huán)境退出，在Oracle 10g 以前的Standby中，本地和遠(yuǎn)程的歸檔都完成后，聯(lián)機(jī)日志文件才可以被重用，在網(wǎng)絡(luò)速度慢的環(huán)境中，遠(yuǎn)程歸檔的配置會(huì)很大程度的影響節(jié)點(diǎn)的處理能力。而設(shè)置LOG_ARCHIVE_LOCAL_FIRST=true，Oracle 會(huì)先進(jìn)行本地歸檔，本地歸檔結(jié)束后在進(jìn)行遠(yuǎn)程傳遞，同時(shí)使聯(lián)機(jī)日志可以重用，從而減少了網(wǎng)絡(luò)環(huán)境對本地的影響。如果把這個(gè)參數(shù)設(shè)置為FALSE，則相當(dāng)于Oracle 10g 之前的方式，這個(gè)參數(shù)默認(rèn)是True，如果在應(yīng)用中遇到找不到歸檔日志的問題，就可以把這個(gè)參數(shù)改成FALSE.

二、RAC數(shù)據(jù)庫的RMAN備份

RAC 和單實(shí)例數(shù)據(jù)庫備份機(jī)制是一樣的，有兩點(diǎn)需要注意：

（1）?????? RMAN 要連接到集群中的某個(gè)實(shí)例，而不是連接到整個(gè)集群

（2）?????? 備份歸檔日志時(shí)，必須保證在備份實(shí)例上能夠訪問所有實(shí)例的歸檔日志，否則就會(huì)報(bào)錯(cuò)。

2.1 先看一個(gè)歸檔日志不一致的問題

?????? 在這種情況下備份是會(huì)報(bào)錯(cuò)的。之前啟動(dòng)歸檔之后，2個(gè)節(jié)點(diǎn)的歸檔目錄文件是相同的，現(xiàn)在我們模擬歸檔日志不一致的情況。

先關(guān)閉兩個(gè)節(jié)點(diǎn)的歸檔位置2。此時(shí)歸檔日志都不能傳遞到對方的歸檔的目錄下。

SQL> alter system set log_archive_dest_state_2 =defer scope=both? sid='*';

System altered.

在手動(dòng)檔產(chǎn)生歸檔日志：

SQL> alter system switch logfile;

System altered.

此時(shí)兩個(gè)節(jié)點(diǎn)歸檔目錄下文件不一致。我們連接到rac1節(jié)點(diǎn)，然后用rman 備份一下，看報(bào)什么錯(cuò)

RMAN> backup database plus archivelog;

Starting backup at 20-SEP-10

current log archived

using channel ORA_DISK_1

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of backup plus archivelog command at 09/20/2010 14:13:32

RMAN-06059: expected archived log not found, lost of archived log compromises recoverability

ORA-19625: error identifying file /u02/rac2_arch/2_11_730181171.dbf

ORA-27037: unable to obtain file status

Linux Error: 2: No such file or directory

Additional information: 3

這里報(bào)錯(cuò)了。現(xiàn)在我們手動(dòng)把缺失的日志從rac2節(jié)點(diǎn)copy到節(jié)點(diǎn)1. 然后啟用歸檔位置2.

SQL> alter system set log_archive_dest_state_2 =enable scope=both? sid='*';

System altered.

然后在備份一下看看。

RMAN> backup database plus archivelog;

Starting backup at 20-SEP-10

current log archived

using channel ORA_DISK_1

channel ORA_DISK_1: starting archive log backupset

channel ORA_DISK_1: specifying archive log(s) in backup set

input archive log thread=1 sequence=11 recid=29 stamp=730213616

input archive log thread=1 sequence=15 recid=36 stamp=730217603

input archive log thread=1 sequence=16 recid=40 stamp=730221061

input archive log thread=1 sequence=17 recid=45 stamp=730222093

input archive log thread=2 sequence=1 recid=3 stamp=730194853

input archive log thread=2 sequence=2 recid=4 stamp=730194856

input archive log thread=2 sequence=3 recid=14 stamp=730195685

input archive log thread=2 sequence=4 recid=20 stamp=730196124

input archive log thread=2 sequence=5 recid=23 stamp=730204019

input archive log thread=2 sequence=6 recid=25 stamp=730205106

input archive log thread=2 sequence=7 recid=27 stamp=730206847

input archive log thread=2 sequence=8 recid=28 stamp=730213614

input archive log thread=2 sequence=11 recid=37 stamp=730217603

input archive log thread=2 sequence=12 recid=41 stamp=730221072

input archive log thread=2 sequence=13 recid=44 stamp=730222092

channel ORA_DISK_1: starting piece 1 at 20-SEP-10

channel ORA_DISK_1: finished piece 1 at 20-SEP-10

piece handle=+FLASH_RECOVERY_AREA/orcl/backupset/2010_09_20/annnf0_tag20100920t152820_0.265.730222103 tag=TAG20100920T152820 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:37

Finished backup at 20-SEP-10

Starting backup at 20-SEP-10

using channel ORA_DISK_1

channel ORA_DISK_1: starting full datafile backupset

channel ORA_DISK_1: specifying datafile(s) in backupset

input datafile fno=00001 name=+DATA/orcl/datafile/system.276.730181051

input datafile fno=00003 name=+DATA/orcl/datafile/sysaux.277.730181053

input datafile fno=00002 name=+DATA/orcl/datafile/undotbs1.278.730181053

input datafile fno=00005 name=+DATA/orcl/datafile/undotbs2.284.730181347

input datafile fno=00004 name=+DATA/orcl/datafile/users.279.730181053

channel ORA_DISK_1: starting piece 1 at 20-SEP-10

channel ORA_DISK_1: finished piece 1 at 20-SEP-10

piece handle=+FLASH_RECOVERY_AREA/orcl/backupset/2010_09_20/nnndf0_tag20100920t152900_0.266.730222143 tag=TAG20100920T152900 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:02:28

channel ORA_DISK_1: starting full datafile backupset

channel ORA_DISK_1: specifying datafile(s) in backupset

including current control file in backupset

including current SPFILE in backupset

channel ORA_DISK_1: starting piece 1 at 20-SEP-10

channel ORA_DISK_1: finished piece 1 at 20-SEP-10

piece handle=+FLASH_RECOVERY_AREA/orcl/backupset/2010_09_20/ncsnf0_tag20100920t152900_0.267.730222301 tag=TAG20100920T152900 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15

Finished backup at 20-SEP-10

Starting backup at 20-SEP-10

current log archived

using channel ORA_DISK_1

channel ORA_DISK_1: starting archive log backupset

channel ORA_DISK_1: specifying archive log(s) in backup set

input archive log thread=1 sequence=18 recid=49 stamp=730222306

input archive log thread=2 sequence=14 recid=48 stamp=730222306

channel ORA_DISK_1: starting piece 1 at 20-SEP-10

channel ORA_DISK_1: finished piece 1 at 20-SEP-10

piece handle=+FLASH_RECOVERY_AREA/orcl/backupset/2010_09_20/annnf0_tag20100920t153150_0.268.730222313 tag=TAG20100920T153150 comment=NONE

channel ORA_DISK_1: backup set complete, elapsed time: 00:00:04

Finished backup at 20-SEP-10

RMAN>　　

2.2 歸檔文件的刪除問題

在上面?zhèn)浞莩晒?#xff0c;這里有一個(gè)新問題，就是對歸檔文件的刪除。通常我們習(xí)慣于在備份完歸檔之后刪除原歸檔文件，以釋放相應(yīng)的磁盤空間，不過在RAC環(huán)境下，只能刪除節(jié)點(diǎn)1上的歸檔文件，節(jié)點(diǎn)2上的無法刪除。因?yàn)樵诠?jié)點(diǎn)1上操作不了節(jié)點(diǎn)2上的歸檔文件。

這個(gè)問題我們可以通過配置通道來解決。一般有幾個(gè)實(shí)例，我們就配置幾個(gè)通道。配置通道命令如下：

RMAN> configure channel 1 device type disk connect 'sys/oracle@orcl1';

new RMAN configuration parameters:

CONFIGURE CHANNEL 1 DEVICE TYPE DISK CONNECT? 'sys/oracle@orcl1';

new RMAN configuration parameters are successfully stored

RMAN> configure channel 2 device type disk connect 'sys/oracle@orcl2';

new RMAN configuration parameters:

CONFIGURE CHANNEL 2 DEVICE TYPE DISK CONNECT? 'sys/oracle@orcl2';

new RMAN configuration parameters are successfully stored

RMAN>　

查看通道情況：

RMAN> show channel;

RMAN configuration parameters are:

CONFIGURE CHANNEL 1 DEVICE TYPE DISK CONNECT? 'sys/oracle@orcl1';

CONFIGURE CHANNEL 2 DEVICE TYPE DISK CONNECT? 'sys/oracle@orcl2';

關(guān)于RMAN 通道，在我blog：

RMAN 系列（二） ---- RMAN 設(shè)置和配置

http://blog.csdn.net/tianlesoftware/archive/2010/06/16/5674309.aspx

中的3.4節(jié)：配置RMAN默認(rèn)設(shè)置中有介紹。

這樣設(shè)置通道除了能刪除其他節(jié)點(diǎn)的歸檔日志外， RMAN還能夠智能的對備份中出現(xiàn)"問題"的任務(wù)進(jìn)行再分配，比如說通道1和通道2同時(shí)執(zhí)行備份，其中通道1備份數(shù)據(jù)文件1，3，4，通道2備份數(shù)據(jù)文件2和5，假如通道2執(zhí)行過程中由于某些原因崩潰，RMAN可以自動(dòng)將任務(wù)放回到通道1上執(zhí)行。

剛才已經(jīng)配置過2個(gè)不同的通道，現(xiàn)在我們來刪除歸檔文件試試：

RMAN> crosscheck archivelog all;

released channel: ORA_DISK_1

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=130 instance=orcl1 devtype=DISK