[20140416]使用dgmgrl管理dataguard(3).txt
参考链接：
http://blog.itpub.net/267265/viewspace-1142649/
http://blog.itpub.net/267265/viewspace-1143027/
从前面的测试看配置启用dgmgrl还是非常简单的。不需要太多的命令。举一些例子来说明：
1.关闭dataguard数据库。看看情况。
SYS@testdg> shutdown immediate ;
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
DGMGRL> show configuration verbose
Configuration - study
Protection Mode: MaxPerformance
Databases:
test - Primary database
Error: ORA-16778: redo transport error for one or more databases
testdg - Physical standby database (disabled)
Properties:
FastStartFailoverThreshold = '30'
OperationTimeout = '30'
FastStartFailoverLagLimit = '30'
CommunicationTimeout = '180'
FastStartFailoverAutoReinstate = 'TRUE'
FastStartFailoverPmyShutdown = 'TRUE'
BystandersFollowRoleChange = 'ALL'
Fast-Start Failover: DISABLED
Configuration Status:
ERROR
DGMGRL> show database testdg
Database - testdg
Role: PHYSICAL STANDBY
Intended State: OFFLINE
Transport Lag: (unknown)
Apply Lag: (unknown)
Real Time Query: OFF
Instance(s):
testdg
Database Status:
SHUTDOWN
--可以发现提示dg处于关闭状态。
2.启动dataguard到mount状态。
DGMGRL> show configuration verbose
Configuration - study
Protection Mode: MaxPerformance
Databases:
test - Primary database
testdg - Physical standby database
Properties:
FastStartFailoverThreshold = '30'
OperationTimeout = '30'
FastStartFailoverLagLimit = '30'
CommunicationTimeout = '180'
FastStartFailoverAutoReinstate = 'TRUE'
FastStartFailoverPmyShutdown = 'TRUE'
BystandersFollowRoleChange = 'ALL'
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS
DGMGRL> show database testdg
Database - testdg
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 0 seconds
Apply Lag: 0 seconds
Real Time Query: OFF
Instance(s):
testdg
Database Status:
SUCCESS
--可以发现redo 日志自动传输，不需要在输入alter database recover managed standby database using current logfile disconnect ;之类的命令。
--从以下命令也可以看出redo日志在传输：
SYS@testdg> select process, status, thread#, sequence#, block#, blocks from v$managed_standby;
PROCESS STATUS THREAD# SEQUENCE# BLOCK# BLOCKS
--------- ------------ ---------- ---------- ---------- ----------
ARCH CONNECTED 0 0 0 0
ARCH CONNECTED 0 0 0 0
ARCH CLOSING 1 978 18432 74
ARCH CLOSING 1 979 1 231
RFS IDLE 0 0 0 0
RFS IDLE 1 980 165 1
RFS IDLE 0 0 0 0
MRP0 APPLYING_LOG 1 980 165 102400
8 rows selected.
3.启动dataguard到read only状态。
SYS@testdg> alter database open read only;
Database altered.
-- 11G 有一个新特性 read-time apply，日志依旧传输与应用。
DGMGRL> show configuration verbose
Configuration - study
Protection Mode: MaxPerformance
Databases:
test - Primary database
testdg - Physical standby database
Properties:
FastStartFailoverThreshold = '30'
OperationTimeout = '30'
FastStartFailoverLagLimit = '30'
CommunicationTimeout = '180'
FastStartFailoverAutoReinstate = 'TRUE'
FastStartFailoverPmyShutdown = 'TRUE'
BystandersFollowRoleChange = 'ALL'
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS
DGMGRL> show database testdg
Database - testdg
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 0 seconds
Apply Lag: 0 seconds
Real Time Query: ON
Instance(s):
testdg
Database Status:
SUCCESS
--可以发现日志一样在应用。
SYS@testdg> select process, status, thread#, sequence#, block#, blocks from v$managed_standby;
PROCESS STATUS THREAD# SEQUENCE# BLOCK# BLOCKS
--------- ------------ ---------- ---------- ---------- ----------
ARCH CONNECTED 0 0 0 0
ARCH CONNECTED 0 0 0 0
ARCH CLOSING 1 978 18432 74
ARCH CLOSING 1 979 1 231
RFS IDLE 0 0 0 0
RFS IDLE 1 980 760 1
RFS IDLE 0 0 0 0
MRP0 APPLYING_LOG 1 980 760 102400
8 rows selected.
--你也可以在主数据库修改一条记录，看看备用库是否相应也修改这条记录，测试忽略。
总结：
可以发现使用dgmgrl来管理后，一切变的很简单。如果认真理解broker的含义(表示 n.掮客, 经纪人的意思。),
就很容易理解，这些操作在后台已经由ora_dmon_XXX来完成。
下面讲解已经使用了dgmgrl来管理dataguard,在使用sqlplus修改一些相关参数会出现什么情况呢？请看下篇。