The RedoRoutes property has a default value of NULL, which is treated as (LOCAL : ALL) at a primary database.
默认规则是：主库同步日志到所有备库。
The ASYNC redo transport attribute must be explicitly specified for a cascaded destination to enable real-time cascading to that destination.
@开始实时级联备库需要指定ASYNC。
ASYNC = Real-Time Cascading
SYNC = Non Real-Time Cascading
# Real-Time Cascading
DGMGRL> edit database sborcl set property redoroutes='(orcl : orcl03 ASYNC)';
Property "redoroutes" updated
DGMGRL> show configuration;
Configuration - dg_orcl
Protection Mode: MaxPerformance
Members:
orcl - Primary database
sborcl - Physical standby database
orcl03 - Physical standby database (receiving current redo)
# Non Real-Time Cascading
DGMGRL> edit database sborcl set property LogXptMode = 'SYNC';
Property "logxptmode" updated
DGMGRL> edit database sborcl set property redoroutes='(orcl : orcl03)';
Property "redoroutes" updated
DGMGRL> show configuration;
Configuration - dg_orcl
Protection Mode: MaxPerformance
Members:
orcl - Primary database
sborcl - Physical standby database
orcl03 - Physical standby database (receiving archived redo)
Fast-Start Failover: Disabled
Configuration Status:
DISABLED
--Cascaded Standby Databases in Oracle 12c (文档 ID 1542969.1)
A redo routing rule is active if its redo source field specifies the current primary database. If a rule is active, primary database redo is sent by the database at which the rule is defined to each destination specified in the redo destination field of that rule.
The RedoRoutes property cannot be configured such that when a physical standby database is converted to a snapshot standby, the snapshot standby would send redo data to another member.
The RedoRoutes property can be set for a logical standby database only if the redo source field is set to LOCAL
