19c ADG部署

時間 2020-02-18

標籤 19c adg 部署欄目 C&C++ 简体版

原文原文鏈接

因客戶須要部署19c DG環境，之前一直是11g和12c部署，故測試下19c部署java

1、DG基礎環境sql

ORACLE 主庫IP：111.111.111.203 SID:DT db_name='DT' 主機名：test19c數據庫

ORACLE 備庫IP：111.111.111.204 SID:dgtest db_name='DT' 主機名：testdg19cwindows

主庫歸檔目錄物理路徑：bash

SQL> archive log list網絡

/u01/app/oracle/product/19.0.0/dbhome_1/dbs/archsession

主庫datafile物理路徑oracle

/u01/app/oradata/app

/u01/app/oradata/DTide

主庫redo物理路徑

/u01/app/oradata/DT

參數*log_archive_config='dg_config(pri,std)'，以確保主備庫數據庫可以互相識別對方。

查看歸檔是否有報錯

select status,error from v$archive_dest;

2、修改主庫配置文件initTESTDB.ora

這裏如今數據庫裏修改相關的參數，與DG的參數就只與幾個參數相關，大概就是日誌，文件的位置的轉換，GAP的處理，其實GAP已經會自動的處理，不過這裏咱們仍是介紹配置FAL_SERVER,FAL_CLIENT參數。在修改完以後從新建立了pfile文件

先建立spfile，修改完後從新生成pfile

SQL> alter system set LOG_ARCHIVE_CONFIG='DG_CONFIG=(DT,dgtest)';

SQL> alter system set LOG_ARCHIVE_DEST_1='LOCATION=/u01/app/oracle/product/19.0.0/dbhome_1/dbs/arch VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=DT';

SQL> alter system set LOG_ARCHIVE_DEST_2='SERVICE=dgtest LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=dgtest';

SQL> alter system set LOG_ARCHIVE_DEST_STATE_1=ENABLE;

SQL> alter system set FAL_SERVER=dgtest;

SQL> alter system set FAL_CLIENT=DT;

SQL> alter system set DB_FILE_NAME_CONVERT='/u01/app/oradata/dgtest','/u01/app/oradata/DT' scope=spfile;

SQL> alter system set LOG_FILE_NAME_CONVERT='/u01/app/oradata/dgtest','/u01/app/oradata/DT' scope=spfile;

SQL> alter system set STANDBY_FILE_MANAGEMENT=AUTO;

SQL> create pfile from spfile;

DB_FILE_NAME_CONVERT和LOG_FILE_NAME_CONVERT參數必須重啓數據庫生效

下面是修改好以後從新生成的pfile文件

DT.__data_transfer_cache_size=0

DT.__db_cache_size=247463936

DT.__inmemory_ext_roarea=0

DT.__inmemory_ext_rwarea=0

DT.__java_pool_size=4194304

DT.__large_pool_size=20971520

DT.__oracle_base='/u01/app'#ORACLE_BASE set from environment

DT.__pga_aggregate_target=293601280

DT.__sga_target=549453824

DT.__shared_io_pool_size=16777216

DT.__shared_pool_size=243269632

DT.__streams_pool_size=0

DT.__unified_pga_pool_size=0

*.audit_file_dest='/u01/app/admin/DT/adump'

*.audit_trail='db'

*.compatible='19.0.0'

*.control_files='/u01/app/oradata/DT/control01.ctl','/u01/app/oradata/DT/control02.ctl'

*.db_block_size=8192

*.db_file_name_convert='/u01/app/oradata/dgtest','/u01/app/oradata/DT'

*.db_name='DT'

*.db_unique_name='DT'

*.diagnostic_dest='/u01/app'

*.dispatchers='(PROTOCOL=TCP) (SERVICE=DTXDB)'

*.fal_client='DT'

*.fal_server='dgtest'

*.local_listener='LISTENER_DT'

*.log_archive_config='DG_CONFIG=(DT,dgtest)'

*.log_archive_dest_1='LOCATION=/u01/app/oracle/product/19.0.0/dbhome_1/dbs/arch VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=DT'

*.log_archive_dest_2='SERVICE=dgtest LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=dgtest'

*.log_archive_dest_state_1='ENABLE'

*.log_file_name_convert='/u01/app/oradata/dgtest','/u01/app/oradata/DT'

*.memory_max_target=903741824

*.memory_target=839524096

*.nls_language='AMERICAN'

*.nls_territory='AMERICA'

*.open_cursors=300

*.processes=480

*.remote_login_passwordfile='EXCLUSIVE'

*.standby_file_management='AUTO'

*.undo_tablespace='UNDOTBS1'

3、修改備庫的配置文件爲：initdgtest.ora

DT.__data_transfer_cache_size=0

DT.__db_cache_size=339738624

DT.__inmemory_ext_roarea=0

DT.__inmemory_ext_rwarea=0

DT.__java_pool_size=4194304

DT.__large_pool_size=20971520

DT.__oracle_base='/u01/app/oracle'#ORACLE_BASE set from environment

DT.__pga_aggregate_target=201326592

DT.__sga_target=641728512

DT.__shared_io_pool_size=12582912

DT.__shared_pool_size=247463936

DT.__streams_pool_size=0

DT.__unified_pga_pool_size=0

*.audit_file_dest='/u01/app/admin/dgtest/adump'

*.audit_trail='db'

*.compatible='19.0.0'

*.control_files='/u01/app/oradata/dgtest/control01.ctl','/u01/app/oradata/dgtest/control02.ctl'

*.db_block_size=8192

*.db_file_name_convert='/u01/app/oradata/DT','/u01/app/oradata/dgtest'

*.db_name='DT'

*.db_unique_name='dgtest'

*.diagnostic_dest='/u01/app'

*.dispatchers='(PROTOCOL=TCP) (SERVICE=dgtestXDB)'

*.fal_client='dgtest'

*.fal_server='DT'

*.local_listener='LISTENER_dgtest'

*.log_archive_config='DG_CONFIG=(DT,dgtest)'

*.log_archive_dest_1='LOCATION=/u01/arch VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=dgtest'

*.log_archive_dest_2='SERVICE=DT LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=DT'

*.log_archive_dest_state_1='ENABLE'

*.log_file_name_convert='/u01/app/oradata/DT','/u01/app/oradata/dgtest'

*.memory_max_target=903741824

*.memory_target=839524096

*.nls_language='AMERICAN'

*.nls_territory='AMERICA'

*.open_cursors=300

*.processes=480

*.remote_login_passwordfile='EXCLUSIVE'

*.standby_file_management='AUTO'

*.undo_tablespace='UNDOTBS1'

注意：

1> Linux端配置的pfile文件中，全部windows的路徑都要用大寫，由於在duplication過程當中，windows端都是按照大寫路徑來傳輸的！

若是用小寫或者大小寫混合，則沒法識別路徑，會有問題！

2> 在duplication過程當中，雖然是在主庫操做，可是datafile和logfile的路徑轉換卻認的是備庫的pfile文件中的轉換路徑！

4、修改主庫的listener.ora文件 ---若是不配置會報錯rman-04006 ora-12514

# listener.ora Network Configuration File: /u01/app/oracle/product/19.0.0/dbhome_1/network/admin/listener.ora

# Generated by Oracle configuration tools.

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = test19c)(PORT = 1521))

(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))

)

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(GLOBAL_DBNAME = DT)

(ORACLE_HOME = /u01/app/oracle/product/19.0.0/dbhome_1)

(SID_NAME = DT)

)

ADR_BASE_LISTENER = D:\app\Administrator

5、修改主庫的tnsnames.ora文件

# tnsnames.ora Network Configuration File: /u01/app/oracle/product/19.0.0/dbhome_1/network/admin/tnsnames.ora

# Generated by Oracle configuration tools.

LISTENER_DT =

(ADDRESS = (PROTOCOL = TCP)(HOST = test19c)(PORT = 1521))

DT =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = test19c)(PORT = 1521))

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = DT)

)

dgtest =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = testdg19c)(PORT = 1521))

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = dgtest)

)

6、修改備庫的listener.ora文件

# listener.ora Network Configuration File: /u01/app/oracle/product/19.0.0/dbhome_1/network/admin/listener.ora

# Generated by Oracle configuration tools.

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = testdg19c)(PORT = 1521))

(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))

)

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(SID_NAME = CLRExtProc)

(ORACLE_HOME = /u01/app/oracle/product/19.2.0/dbhome_1)

(PROGRAM = extproc)

#(ENVS = "EXTPROC_DLLS=ONLY:/u01/app/oracle/product/19.2.0/dbhome_1/oraclr11.dll")

)

(SID_DESC =

(GLOBAL_DBNAME = dgtest)

(ORACLE_HOME = /u01/app/oracle/product/19.2.0/dbhome_1)

(SID_NAME = dgtest)

)

7、修改備庫的tnsnames.ora文件

# tnsnames.ora Network Configuration File: /u01/app/oracle/product/19.0.0/dbhome_1/network/admin/tnsnames.ora

# Generated by Oracle configuration tools.

LISTENER_DT =

(ADDRESS = (PROTOCOL = TCP)(HOST = test19c)(PORT = 1521))

DT =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = test19c)(PORT = 1521))

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = DT)

)

dgtest =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = testdg19c)(PORT = 1521))

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = dgtest)

)

8、備庫生成orapwd文件

orapwd file=orapwdgtest password=oracle

注：爲防止密碼問題致使沒法訪問，最好直接把主庫的orapw文件拷貝過來而後改名orapwSID就能夠了

9、確認主庫和備庫都啓動監聽：lsnrctl start

10、主庫設置爲歸檔模式

alter database archivelog

設置主數據庫爲日誌強制寫狀態

alter database force logging;

查看狀態日誌強制寫狀態爲YES

select log_mode,force_logging from v$database;

LOG_MODE FOR

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

ARCHIVELOG YES

11、查看主庫數據庫的日誌組個數與大小，由於咱們建立standby日誌組的個數是原日誌組個數+1再與thread的積，size不能小於原日誌文件的大小。

SQL> select group#,THREAD#,bytes/1024/1024 from v$log;

GROUP# THREAD# BYTES/1024/1024

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

1 1 200

2 1 200

3 1 200

SQL> select member from v$logfile;

MEMBER

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

/u01/app/oradata/DT/redo03.log

/u01/app/oradata/DT/redo02.log

/u01/app/oradata/DT/redo01.log

12、建立standby日誌組，個數是原日誌組個數+1再與實例數的積，size不能小於原日誌文件的大小

注：RAC環境注意實例有幾個，新建standby日誌組的路徑可與原日誌組相同。

SQL> alter database add standby logfile '/u01/app/oradata/DT/standby01.log' size 200m;

Database altered.

alter database add standby logfile '/u01/app/oradata/DT/standby01.log' size 200m;

alter database add standby logfile '/u01/app/oradata/DT/standby02.log' size 200m;

alter database add standby logfile '/u01/app/oradata/DT/standby03.log' size 200m;

alter database add standby logfile '/u01/app/oradata/DT/standby04.log' size 200m;

建立完成後查詢是否成功

SQL> select group#,status,type,member from v$logfile;

GROUP# STATUS TYPE MEMBER

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

3 ONLINE /u01/app/oradata/DT/redo03.log

2 ONLINE /u01/app/oradata/DT/redo02.log

1 ONLINE /u01/app/oradata/DT/redo01.log

4 STANDBY /u01/app/oradata/DT/standby01.log

5 STANDBY /u01/app/oradata/DT/standby02.log

6 STANDBY /u01/app/oradata/DT/standby03.log

7 STANDBY /u01/app/oradata/DT/standby04.log

7 rows selected.

13、啓動備庫到NOMOUNT

$ sqlplus / as sysdba

SQL> startup nomount pfile='/home/oracle/backup/INITtestdb.ORA';

注：若是pfile文件放在默認路徑，且文件名正確的話。不須要指定pfile路徑，直接startup nomount便可。

14、duplicate開始

在主庫上經過rman進行復製備庫(注意在這一步以前必須退出備庫的全部鏈接,不然會報錯)

rman target sys/oracle auxiliary sys/oracle@dgtest

rman> duplicate target database for standby nofilenamecheck from active database;

經資料查詢，發如今duplicate傳輸時，windows下所有是大寫字符，因此，還得修改

DB_FILE_NAME_CONVERT和LOG_FILE_NAME_CONVERT參數的路徑，全用大寫

*************************錯誤信息*************************

19c測試時因爲備庫的環境變量ORACLE_HOME配置有誤，致使始終沒法鏈接到備庫，報錯以下：

[oracle@test19c admin]$ rman target sys/oracle auxiliary sys/oracle@dgtest

Recovery Manager: Release 19.0.0.0.0 - Production on Mon Jun 17 18:13:10 2019

Version 19.2.0.0.0

connected to target database: DT (DBID=1254913786)

connected to auxiliary database (not started)

RMAN> exit

檢查發如今.bash_profile文件中，ORACLE_BASE的路徑最後加了一個/，致使在ORACLE_HOME中多了一個/

ORACLE_BASE=/u01/app/oracle/; export ORACLE_BASE ---/u01/app/oracle不應多那個/啊。。。

ORACLE_HOME=$ORACLE_BASE/product/19.2.0/dbhome_1; export ORACLE_HOME

最終使用echo $ORACLE_HOME時看到的路徑以下：

/u01/app/oracle//product/19.2.0/dbhome_1

可是最無奈的是你輸入cd $ORACLE_HOME的時候卻能夠進入正確的路徑，而後pwd會顯示：/u01/app/oracle/product/19.2.0/dbhome_1

因此以前檢查時，始終認爲環境變量沒有問題。最終將ORACLE_BASE修改成/u01/app/oracle 而後重啓監聽，重啓備庫就行了

總結：仍是使用echo來檢查各類環境變量，不要直接cd進去檢查。

------分割線------

注意db_recovery_file_dest_size的大小，上次部署12c生產環境就是大小有問題，修改後解決：

SQL> alter system set db_recovery_file_dest_size=60G;

***************************End***************************

15、open備庫，並恢復到自動恢復狀態

確認備庫狀態：

SQL> select open_mode from v$database;

OPEN_MODE

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

MOUNTED

把備庫啓動到open only下面：

SQL> alter database open read only;

在備庫上啓動數據庫到恢復管理模式，並開始準備從主庫接受歸檔日誌的傳輸：

SQL> alter database recover managed standby database using current logfile disconnect from session;

*************************錯誤信息*************************

備庫啓動報錯：

SQL> alter database open read only;

alter database open read only

ERROR at line 1:

ORA-10458: standby database requires recovery

ORA-01152: file 1 was not restored from a sufficiently old backup

ORA-01110: data file 1: '/u01/app/oradata/dgtest/system01.dbf'

在主備庫上查看alert日誌，發現備庫alert日誌有以下信息：

PR00 (PID:7481): Please verify that primary database is transporting redo logs to the standby database

根據信息檢查，發現redo根本沒過來，由於在備庫歸檔目錄沒有看到一個歸檔文件！！！

目前定位就是沒法傳輸歸檔，因而在主備庫檢查歸檔是否有報錯：

select status,error from v$archive_dest;

在主庫發現報錯：

SQL> select status,error from v$archive_dest;

STATUS ERROR

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

VALID

ERROR ORA-16086: Redo data cannot be written to the standby redo log

這種報錯通常也是和配置文件相關，網上也有相關文檔和排錯思路。

通過屢次測試發現是和db_unique_name參數沒有配置有關：

檢查發現備庫的db_unique_name在沒有配置的狀況下默認也叫DT，和主庫一致。

這就致使了主備庫由於db_unique_name一致而沒法區分，進而致使redo沒法傳輸，也就沒有歸檔了。

SQL> show parameter name

NAME TYPE VALUE

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

cdb_cluster_name string

cell_offloadgroup_name string

db_file_name_convert string /u01/app/oradata/DT, /u01/app/oradata/dgtest

db_name string DT

db_unique_name string DT

global_names boolean FALSE

instance_name string dgtest

lock_name_space string

log_file_name_convert string /u01/app/oradata/DT, /u01/app/oradata/dgtest

pdb_file_name_convert string

processor_group_name string

service_names string DT

SQL>

上面的信息能夠看到instance_name是dgtest，可是db_unique_name仍是DT，因此致使redo沒法傳輸。

最後在備庫上修改pfile文件，加上db_unique_name的配置就解決問題了。

最好是主備庫都在pfile中定義一下db_unique_name!

本次部署環境，19c主庫安裝好後，生成的pfile沒有定義db_unique_name，因此也就忽略了這個問題。

-------分割線，下面步驟操做有問題，應該先open庫----------

回到原主庫啓動STANDBY開始接收並恢復主庫的日誌

alter database recover managed standby database using current logfile disconnect from session;

在mount狀態下輸入上面語句，致使數據庫沒法open,因此須要退出這個狀態

alter database recover managed standby database cancel;

***************************End***************************

16、主庫檢查LNS進程：

select process,status from v$managed_standby;

查看進程，看有沒有LNS進程，若是沒有則須要檢查DG環境

SQL> select process,status from v$managed_standby;

PROCESS STATUS

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

DGRD ALLOCATED

ARCH CLOSING

DGRD ALLOCATED

ARCH OPENING

ARCH CONNECTED

LNS OPENING

DGRD ALLOCATED

LNS WRITING

9 rows selected.

17、檢查主備庫角色和其餘信息

在備庫端查看其角色是否已是physical standby,檢查當前備庫的模式PROTECTION_MODE

SQL> select DATABASE_ROLE,protection_mode,open_mode from v$database;

DATABASE_ROLE PROTECTION_MODE OPEN_MODE

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

PHYSICAL STANDBY MAXIMUM PERFORMANCE READ ONLY WITH APPLY

在主庫查看其角色

SQL> select DATABASE_ROLE,open_mode from gv$database;

DATABASE_ROLE OPEN_MODE

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

PRIMARY READ WRITE

在備庫查看data guard爲哪一種日誌接受方式

SQL> select process,client_process,sequence#,status from v$managed_standby;

PROCESS CLIENT_P SEQUENCE# STATUS

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

ARCH ARCH 0 CONNECTED

DGRD N/A 0 ALLOCATED

ARCH ARCH 0 CONNECTED

RFS Archival 0 IDLE

RFS LGWR 31 IDLE

RFS UNKNOWN 0 IDLE

MRP0 N/A 31 APPLYING_LOG

10 rows selected.

18、檢查主備庫sequence#

select max(sequence#) from v$archived_log;

select sequence#,name,standby_dest,applied,deleted from v$archived_log where archived='YES' order by sequence# desc;

主庫：

SQL> select max(sequence#) from v$archived_log;

MAX(SEQUENCE#)

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

備庫

SQL> select max(sequence#) from v$archived_log;

MAX(SEQUENCE#)

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

19、測試日誌隊列是否能正常傳輸

在備庫查看日誌的隊列狀況

SQL> select sequence#,applied,first_time,next_time from v$archived_log order by sequence#;

SEQUENCE# APPLIED FIRST_TIM NEXT_TIME

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

30 YES 18-JUN-19 18-JUN-19

在主庫進行強制歸檔

ALTER SYSTEM ARCHIVE LOG CURRENT;

alter system switch logfile;

在備庫查看日誌的隊列狀況,看新的歸檔日誌有沒有正常傳輸過來

SQL> select sequence#,applied,first_time,next_time from v$archived_log order by sequence#;

SEQUENCE# APPLIED FIRST_TIM NEXT_TIME

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

30 YES 18-JUN-19 18-JUN-19

31 NO 18-JUN-19 18-JUN-19

32 IN-MEMORY 18-JUN-19 18-JUN-19

檢查下兩邊的日誌同步狀況

select sequence# from v$archived_log where applied='YES';

看看有沒有寫的redo log:

select sequence#,applied from v$archived_log;

20、查看DG是否正常工做，這一步主要看歸檔有無報錯

select dest_id,error,status from v$archive_dest where status='ERROR';

SQL> select dest_id,error,status from v$archive_dest where status='ERROR';

no rows selected

也能夠直接查看全部歸檔目錄信息：

select dest_id,error,status from v$archive_dest

21、在主庫新建表空間、用戶、表，並插入數據來測試備庫是否能及時同步數據

主庫建立測試表空間：

SQL> create tablespace test datafile '/u01/app/oradata/DT/dt01.dbf' size 50m;

主備庫查看數據文件狀態

select FILE#,CREATION_TIME,STATUS,NAME,BYTES from v$datafile;

主庫：

SQL> select FILE#,CREATION_TIME,STATUS,NAME,BYTES from v$datafile;

FILE# CREATION_ STATUS NAME BYTES

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

1 04-FEB-19 SYSTEM /u01/app/oradata/DT/system01.dbf 943718400

3 04-FEB-19 ONLINE /u01/app/oradata/DT/sysaux01.dbf 555745280

4 04-FEB-19 ONLINE /u01/app/oradata/DT/undotbs01.dbf 68157440

5 18-JUN-19 ONLINE /u01/app/oradata/DT/dt01.dbf 52428800

7 04-FEB-19 ONLINE /u01/app/oradata/DT/users01.dbf 5242880

備庫：

SQL> select FILE#,CREATION_TIME,STATUS,NAME,BYTES from v$datafile;

FILE# CREATION_ STATUS NAME BYTES

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

1 04-FEB-19 SYSTEM /u01/app/oradata/dgtest/system01.dbf 943718400

3 04-FEB-19 ONLINE /u01/app/oradata/dgtest/sysaux01.dbf 555745280

4 04-FEB-19 ONLINE /u01/app/oradata/dgtest/undotbs01.dbf 68157440

5 18-JUN-19 ONLINE /u01/app/oradata/dgtest/dt01.dbf 52428800

7 04-FEB-19 ONLINE /u01/app/oradata/dgtest/users01.dbf 5242880

主庫操做：

1> 建立用戶

create user dgtest default tablespace test identified by oracle;

grant dba to dgtest;

2> 切換用戶

sqlplus dgtest/oracle

3> dgtest用戶下建立表和插入測試數據

--建立表

create table dgtest (

id number(9) not null primary key,

classname varchar2(40) not null

);

--插入數據

insert into dgtest values(28,'class one');

insert into dgtest values(29,'detest one');

commit;

在備庫執行查詢：

select * from dgtest.dgtest;

SQL> select * from dgtest.dgtest;

ID CLASSNAME

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

28 class one

29 detest one

刪除測試數據：

drop tablespace test including contents and datafiles;

drop user dgtest cascade;

到此DG環境部署完畢，數據能夠正常同步。

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

------------------------主備庫切換測試------------------------

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

#切換的兩種方式switchover和failover

switchover 切換：主庫與備庫數據同步正常狀況下的切換，主要用於主備維護、切換演練等；

failover 切換：主庫與備庫在數據未同步狀況下的強制切換，主要用於主庫宕機、故障狀況下切換；

1、switchover

Oracle 物理DG切換

在進行DATA GUARD的物理STANDBY切換前須要注意：

確認主庫和備庫間網絡鏈接通暢；

確認沒有活動的會話鏈接在數據庫中；

確保STANDBY數據庫處於ARCHIVELOG模式；

若是設置了REDO應用的延遲，那麼將這個設置去掉；

確保配置了主庫和備庫的初始化參數，使得切換完成後，DATA GUARD機制能夠順利的運行。

#準備工做：

確認當前主庫只有當前會話鏈接:

set pages 100 linesize 1000;

select SWITCHOVER_STATUS from v$database;

SQL> select SWITCHOVER_STATUS from v$database;

SWITCHOVER_STATUS

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

TO STANDBY

select count(*) from v$session where username is not null;

SQL> select count(*) from v$session where username is not null;

COUNT(*)

----------

如有多於一個會話則：

select sid,serial# from v$session where username is not null;

SQL> select sid,serial# from v$session where username is not null;

SID SERIAL#

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

2 10746

621 13864

select userenv('sid') from dual;

SQL> select userenv('sid') from dual;

USERENV('SID')

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

621

則執行下面語句殺掉：alter system kill session 'sid,serial#';

SQL> alter system kill session '621,13864';

alter system kill session '621,13864'

ERROR at line 1:

ORA-00027: cannot kill current session

原來621是當前會話，能夠不用理會。

#正式切換：

主庫與備庫數據同步，且正常運行，將主庫與備庫的角色互換，也能夠互換回來。

切換前，務必檢查當前主庫與備庫的歸檔是不是同步的，確認同步後再執行切換

主庫切備庫

1、查看庫的角色

主庫：

SQL> select CONTROLFILE_TYPE,OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS from V$DATABASE;

CONTROL OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

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

CURRENT READ WRITE PRIMARY TO STANDBY

SWITCHOVER_STATUS爲TO STANDBY，說明主庫能夠切換爲備庫

備庫：

SQL> select CONTROLFILE_TYPE,OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS from V$DATABASE;

CONTROL OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

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

STANDBY READ ONLY PHYSICAL STANDBY NOT ALLOWED

SWITCHOVER_STATUS爲NOT ALLOWED，這是備庫的正常狀態。

在主庫首先切換後，咱們再查詢備庫狀態會發現SWITCHOVER_STATUS有改變

2、對主庫進行切換

SQL> alter database commit to switchover to physical standby with session shutdown;

此時主庫已經開始切換到備庫的過程了，而備庫的SWITCHOVER_STATUS已經變成TO PRIMARY

3、此時主庫已經關閉，打到read only或同步狀態

SQL> startup mount;

ORACLE instance started.

Total System Global Area 905967800 bytes

Fixed Size 8902840 bytes

Variable Size 788529152 bytes

Database Buffers 100663296 bytes

Redo Buffers 7872512 bytes

Database mounted.

SQL> alter database open read only;

Database altered.

4、再查主庫的角色，確認已經切換爲備庫

SQL> select CONTROLFILE_TYPE,OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS from V$DATABASE;

CONTROL OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

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

STANDBY READ ONLY PHYSICAL STANDBY TO PRIMARY

注：這一步操做完成後，此時主備庫都是open read only狀態，且SWITCHOVER_STATUS都爲TO PRIMARY。

此時已經沒有真正主庫存在的了，主庫已經切換爲備庫，備庫還未切換成主庫。

也就是說此時主備庫都能切換爲真正的主庫

5、在備庫上啓動數據庫到恢復管理模式，並開始準備從主庫接受歸檔日誌的傳輸。

SQL> alter database recover managed standby database using current logfile disconnect from session;

注：這一步不執行的話，OPEN_MODE狀態始終是READ ONLY，沒法變成正常的READ ONLY WITH APPLY

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING ARCHIVED LOGFILE DISCONNECT;

查資料顯示，12c以後使用上面這個語句來APPLY，黃色部分爲和11gR2的區別

6、再查主庫的角色，確認已經切換爲備庫，且OPEN_MODE爲READ ONLY WITH APPLY

SQL> select CONTROLFILE_TYPE,OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS from V$DATABASE;

CONTROL OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

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

STANDBY READ ONLY WITH APPLY PHYSICAL STANDBY TO PRIMARY

備庫切主庫

1、查看備庫角色：

SQL> select CONTROLFILE_TYPE,OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS from V$DATABASE;

CONTROL OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

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

STANDBY READ ONLY WITH APPLY PHYSICAL STANDBY TO PRIMARY

SWITCHOVER_STATUS爲TO PRIMARY，說明備庫能夠切換爲主庫

2、備切主命令

SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;

3、確認備庫已是mount狀態

SQL> select status,instance_name from v$instance;

STATUS INSTANCE_NAME

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

MOUNTED dgtest

4、打到OPEN狀態

SQL> ALTER DATABASE OPEN;

如今的主庫切換幾回日誌文件，備庫能夠同步日誌文件。

注：只有在備庫OPEN完成切換，成爲新主庫以後，原主庫的SWITCHOVER_STATUS狀態纔會由TO PRIMARY變爲NOT ALLOWED

5、再查備庫的角色，確認已經切換爲主庫

SQL> select CONTROLFILE_TYPE,OPEN_MODE,DATABASE_ROLE,SWITCHOVER_STATUS from V$DATABASE;

CONTROL OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS

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

CURRENT READ WRITE PRIMARY TO STANDBY

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

-----到此，主備庫切換完畢，standby to primary過程已經完成-----

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

2、failover災難切換

主庫宕機，沒法啓動，緊急啓用備庫。直接在備庫上操做，將備庫轉換爲主庫角色

備庫上執行下面四條命令便可：

SQL > alter database recover managed standby database finish;

SQL > alter database commit to switchover to primary;

SQL > shutdown immediate;

SQL > startup;

注：此操做不可逆，ARCH從1開始計數，要從新作全備和部署DG

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