11GR DATAGRUAD环境BROKER配置Fast-Start Failover

 FAST-START failover 就是在当主数据库出现故障时，能快速与可靠的把standby切换成主数据库，在整个过程中不需要人来干预。fast-start failover只能通过dgmgrl与Enterprise Managerg来配置。

  只有maximum availability mode or maximum performance mode才能启用fast-start failover模式。在maximum availability模式下面，在切换时可以保证无数据丢失，在maximum performance mode下面，会有数据丢失，丢失多少数据由 FastStartFailoverLagLimit这个参数来配置。

 只要observer进程启动过，我们就不需要人为的干预。当observer与指定的备数据库与主数据库失去连接的时间超过FastStartFailoverThreshold后，observer就会启动fast-start failover 到备数据库。如果配置了FastStartFailoverPmyShutdown为true，此时原来的主数据库将会自动的shutdown。如果配置FastStartFailoverAutoReinstate为true，当failover完成后，启动数据库时，会自动的执行Reinstate database，把原来的主数据库变成备库，并与新主库进行同步。


  fast-start failover包含3个过程，如下图：

 

测试开始：

   环境：OS REDHAT 5.6 X86_64 ,DB 11.2.0.2

 

1,DG环境的搭建。

见11GR2 搭建活动的物理DG/DATAGRUAD (READ ONLY模式)

http://luoping.blog.51cto.com/534596/983952

2,broker的配置

见 http://luoping.blog.51cto.com/534596/983983

3，配置保护模式与日志传递方式

之前已经说了FAST-START FAILOVER只 maximum availability mode与maximum performance mode

下面我们看一下每一种保护模式对应的日志传递方式。

3.1修改保护模式：

[oracle@test admin]$ dgmgrl
DGMGRL for Linux: Version 11.2.0.2.0 - 64bit Production

Copyright (c) 2000, 2009, Oracle. All rights reserved.

Welcome to DGMGRL, type "help" for information.
DGMGRL> connect sys/oracle@htz
Connected.
#通过help查看命令的帮忙。
DGMGRL> help edit
Edits a configuration, database, or instance
Syntax:

  EDIT CONFIGURATION SET PROTECTION MODE AS
    {MaxProtection|MaxAvailability|MaxPerformance};

  EDIT CONFIGURATION SET PROPERTY <property name> = <value>;

  EDIT DATABASE <database name> SET PROPERTY <property name> = <value>;

  EDIT DATABASE <database name> RENAME TO <new database name>;

  EDIT DATABASE <database name> SET STATE = <state>
    [WITH APPLY INSTANCE = <instance name>];

  EDIT INSTANCE <instance name> [ON DATABASE <database name>]
    SET AUTO PFILE [ = {<initialization file path>|OFF} ];

  EDIT INSTANCE <instance name> [ON DATABASE <database name>]
    SET PROPERTY <property name> = <value>;

  EDIT INSTANCE * ON DATABASE <database name>
    SET PROPERTY <property name> = <value>;

DGMGRL> edit configuration set protection mode as maxavilability;
Syntax error before or at "maxavilability"
DGMGRL> show configuration;

Configuration - htz
#最大可用的保护模式
  Protection Mode: MaxAvailability
  Databases:
    htzb - Primary database
    htz  - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS

3.2 修改日志传递方式

DGMGRL> edit database htz set property logxptmode=sync;
Property "logxptmode" updated
DGMGRL> edit database htzb set property logxptmode=sync;
Property "logxptmode" updated
DGMGRL> show database htz logxptmode
  LogXptMode = 'sync'
DGMGRL> show database htzb logxptmode
  LogXptMode = 'sync

4 配置数据库的flashback

4.1 主库上面

SQL> select open_mode,database_role,log_mode,flashback_on from v$database;

OPEN_MODE            DATABASE_ROLE    LOG_MODE     FLASHBACK_ON
-------------------- ---------------- ------------ ------------------
READ WRITE           PRIMARY          ARCHIVELOG   NO
#配置flashback
SQL> alter database flashback on;

Database altered.

SQL> select open_mode,database_role,log_mode,flashback_on from v$database;

OPEN_MODE            DATABASE_ROLE    LOG_MODE     FLASHBACK_ON
-------------------- ---------------- ------------ ------------------
READ WRITE           PRIMARY          ARCHIVELOG   YES
#flashback的配置目录与大小
SQL> show parameter recovery

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest                string      /u01/app/oracle/fast_recovery_
                                                 area
db_recovery_file_dest_size           big integer 4032M

4.2 备库上面

SQL> select open_mode,database_role,log_mode,flashback_on from v$database;

OPEN_MODE            DATABASE_ROLE    LOG_MODE     FLASHBACK_ON
-------------------- ---------------- ------------ ------------------
READ ONLY WITH APPLY PHYSICAL STANDBY ARCHIVELOG   NO

SQL> recover managed standby database cancel;
Media recovery complete.
SQL> alter database flashback on;

Database altered.

SQL> recover managed standby database using current logfile disconnect;
Media recovery complete.
SQL> select open_mode,database_role,log_mode,flashback_on from v$database;

OPEN_MODE            DATABASE_ROLE    LOG_MODE     FLASHBACK_ON
-------------------- ---------------- ------------ ------------------
READ ONLY WITH APPLY PHYSICAL STANDBY ARCHIVELOG   YES

5 配置observer服务器

5.1 配置tnsnames.ora文件。

[oracle@test admin]$ cat tnsnames.ora
HTZB =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.31)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = dedicate)
      (SERVICE_NAME = htzb)
    )
  )

HTZ =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.30)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = dedicate)
      (SERVICE_NAME = htz)
    )
  )

5.2 启动observer进程

[oracle@test admin]$ dgmgrl sys/oracle@htz "start observer"
DGMGRL for Linux: Version 11.2.0.2.0 - 64bit Production

Copyright (c) 2000, 2009, Oracle. All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected.
Observer started

6 配置fast-start failover

DGMGRL> edit database htz set property FastStartFailoverTarget=htzb;
Property "faststartfailovertarget" updated
DGMGRL> edit database htzb set property  FastStartFailoverTarget=htz;
Property "faststartfailovertarget" updated

于fst-start failove相关的其它几个参数:

FastStartFailoverPmyShutdown

FastStartFailoverLagLimit

FastStartFailoverAutoReinstate

ObserverConnectIdentifier

这里我们都使用默认值;我们来看一下这些值的默认值；

DGMGRL> show configuration verbose;

Configuration - htz

  Protection Mode: MaxAvailability
  Databases:
    htzb - Primary database
    htz  - (*) Physical standby database

  (*) Fast-Start Failover target

  Properties:
    FastStartFailoverThreshold      = '30'
    OperationTimeout                = '30'
    FastStartFailoverLagLimit       = '30'
    CommunicationTimeout            = '180'
    FastStartFailoverAutoReinstate  = 'TRUE'
    FastStartFailoverPmyShutdown    = 'TRUE'
    BystandersFollowRoleChange      = 'ALL'

Fast-Start Failover: DISABLE

  Threshold:        30 seconds
  Target:           htz
  Observer:         test
  Lag Limit:        30 seconds (not in use)
  Shutdown Primary: TRUE
  Auto-reinstate:   TRUE

Configuration Status:
SUCCESS

7 启用fast-start failover

DGMGRL> show configuration

Configuration - htz

  Protection Mode: MaxAvailability
  Databases:
    htzb - Primary database
    htz  - Physical standby database

Fast-Start Failover: DISABLED

Configuration Status:
SUCCESS
DGMGRL> enable fast_start failover
Enabled.
DGMGRL>

8.测试FAST-START FAILOVER是否生效

DGMGRL> show configuration

Configuration - htz

  Protection Mode: MaxAvailability
  Databases:
    htzb - Primary database
    htz  - (*) Physical standby database
Fast-Start Failover: ENABLED
Configuration Status:
SUCCESS
#原主库直接shutdown abort;
SQL> shutdown abort;
ORACLE instance shut down.
SQL>
#observer进程的日志
19:03:03.93  Friday, September 07, 2012Initiating Fast-Start Failover to database "htz"...Performing failover NOW, please wait...Failover succeeded, new primary is "htz"19:03:13.24  Friday, September 07, 2012
#提示已经把主切换到htz
#在htz上面查看一下
SQL> select open_mode ,database_role from v$database;

OPEN_MODE            DATABASE_ROLE
-------------------- ----------------
READ WRITE           PRIMARY
已经成功
手动启动原主库
DGMGRL> show configuration;Configuration - htz  Protection Mode: MaxAvailability  Databases:    htz  - Primary database      Warning: ORA-16817: unsynchronized fast-start failover configuration    htzb - (*) Physical standby database (disabled)      ORA-16661: the standby database needs to be reinstatedFast-Start Failover: ENABLEDConfiguration Status:WARNINGDGMGRL> connect sys/oracle@htzbConnected.DGMGRL> startupORACLE instance started.Database mounted.ORA-16649: possible failover to another database prevents this database from being opened
#过一分会后我们再查看一下状态
DGMGRL> connect sys/oracle@htzConnected.DGMGRL> show configurationConfiguration - htz  Protection Mode: MaxAvailability  Databases:    htz  - Primary database    htzb - (*) Physical standby databaseFast-Start Failover: ENABLEDConfiguration Status:SUCCESS
查看状态，一切正常。