Data Guard Broker中改屬性是否需要兩側分別執行？

Data Guard Broker有一些屬性，可以通過 show configuration 看到。
我有時會想，這些個屬性，是否是分別屬於primary 和 standby，如果
想要修改，是否需要分別登陸到primary 和 standby ，來分別修改呢？

這也是很多客戶經常有的疑問。故此我進行了如下的實驗。

先看看primary 端的 屬性值：

-bash-4.1$ dgmgrl /
DGMGRL for Linux: Version 12.1.0.2.0 - 64bit Production

Copyright (c) 2000, 2013, Oracle. All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected as SYSDG.

DGMGRL> show configuration verbose;

Configuration - DRSolution

 Protection Mode: MaxPerformance
 Members:
 orcl12102      - Primary database
   orcl12102_stby - Physical standby database

 Properties:
   FastStartFailoverThreshold      = '30'
   OperationTimeout                = '30'
   TraceLevel                      = 'USER'
   FastStartFailoverLagLimit       = '30'
   CommunicationTimeout            = '180'　
   ObserverReconnect               = '0'
   FastStartFailoverAutoReinstate  = 'TRUE'
   FastStartFailoverPmyShutdown    = 'TRUE'
   BystandersFollowRoleChange      = 'ALL'
   ObserverOverride                = 'FALSE'
   ExternalDestination1            = ''
   ExternalDestination2            = ''
   PrimaryLostWriteAction          = 'CONTINUE'

Fast-Start Failover: DISABLED

Configuration Status:
SUCCESS

DGMGRL>

再看Standby 端的屬性：

-bash-4.1$ dgmgrl /
DGMGRL for Linux: Version 12.1.0.2.0 - 64bit Production

Copyright (c) 2000, 2013, Oracle. All rights reserved.

Welcome to DGMGRL, type "help" for information.
Connected as SYSDG.

DGMGRL> show configuration verbose;

Configuration - DRSolution

 Protection Mode: MaxPerformance
 Members:
 orcl12102      - Primary database
   orcl12102_stby - Physical standby database

 Properties:
   FastStartFailoverThreshold      = '30'
   OperationTimeout                = '30'
   TraceLevel                      = 'USER'
   FastStartFailoverLagLimit       = '30'
   CommunicationTimeout            = '180'
   ObserverReconnect               = '0'
   FastStartFailoverAutoReinstate  = 'TRUE'
   FastStartFailoverPmyShutdown    = 'TRUE'
   BystandersFollowRoleChange      = 'ALL'
   ObserverOverride                = 'FALSE'
   ExternalDestination1            = ''
   ExternalDestination2            = ''
   PrimaryLostWriteAction          = 'CONTINUE'

Fast-Start Failover: DISABLED

Configuration Status:
SUCCESS

DGMGRL>

從 primary 和 standby 兩邊看到的屬性值都是一樣的。所以我有一個猜測，這些屬性值是共通的。
下面通過修改 CommunicationTimeout 的值來進行驗證：

在primary 端修改：

DGMGRL> EDIT CONFIGURATION SET PROPERTY CommunicationTimeout=120;
Property "communicationtimeout" updated

改完後驗證一下：

DGMGRL> show configuration verbose;

Configuration - DRSolution

 Protection Mode: MaxPerformance
 Members:
 orcl12102      - Primary database
   orcl12102_stby - Physical standby database

 Properties:
   FastStartFailoverThreshold      = '30'
   OperationTimeout                = '30'
   TraceLevel                      = 'USER'
   FastStartFailoverLagLimit       = '30'
   CommunicationTimeout            = '120'　******
   ObserverReconnect               = '0'
   FastStartFailoverAutoReinstate  = 'TRUE'
   FastStartFailoverPmyShutdown    = 'TRUE'
   BystandersFollowRoleChange      = 'ALL'
   ObserverOverride                = 'FALSE'
   ExternalDestination1            = ''
   ExternalDestination2            = ''
   PrimaryLostWriteAction          = 'CONTINUE'

Fast-Start Failover: DISABLED

Configuration Status:
SUCCESS

DGMGRL>

那麼，在 standby 端，會看到怎樣的結果呢？

DGMGRL> show configuration verbose;

Configuration - DRSolution

 Protection Mode: MaxPerformance
 Members:
 orcl12102      - Primary database
   orcl12102_stby - Physical standby database

 Properties:
   FastStartFailoverThreshold      = '30'
   OperationTimeout                = '30'
   TraceLevel                      = 'USER'
   FastStartFailoverLagLimit       = '30'
   CommunicationTimeout            = '120'　<<<<<<<<<<<<<  從 standby 端，也可以看到這個值，確實被改變了。
   ObserverReconnect               = '0'
   FastStartFailoverAutoReinstate  = 'TRUE'
   FastStartFailoverPmyShutdown    = 'TRUE'
   BystandersFollowRoleChange      = 'ALL'
   ObserverOverride                = 'FALSE'
   ExternalDestination1            = ''
   ExternalDestination2            = ''
   PrimaryLostWriteAction          = 'CONTINUE'

Fast-Start Failover: DISABLED

Configuration Status:
SUCCESS

DGMGRL>

事實上，從 standby 端來更改其他的屬性值，也是可以的，我們也可以從primary 端，連線到 data guard broker，看到同樣的改變。

所以說，Data Guard Broker 搭建完畢後，如果想更改其屬性值，無論是從primary 端，還是從standby 端，登陸連線到broker 後，
在哪一端修改都是可以的。