在客户环境中，使用了Oracle 10.2.0.4 DataGuard技术，通过最大可用性模式进行数据保护。
以下简单测试，当备库关闭后，再重启备库，主库及备库的响应过程。
在备库执行如下步骤：
SQL> shutdown immediate;
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 1610612736 bytes
Fixed Size 2084400 bytes
Variable Size 385876432 bytes
Database Buffers 1207959552 bytes
Redo Buffers 14692352 bytes
Database mounted.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;
Database altered.
SQL> exit
当备库关闭后，主库立即检测到备库的失败：
Tue Nov 17 20:34:58 2009
ARC1: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (3113)
ARC1: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
PING[ARC1]: Error 3113 when pinging standby STANDBY.
Tue Nov 17 20:35:17 2009
LGWR: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (3113)
LGWR: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
Tue Nov 17 20:35:17 2009
Errors in file /opt/oracle/admin/oradbt/bdump/oradbt_lgwr_319632.trc:
ORA-03113: end-of-file on communication channel
LGWR: Network asynch I/O wait error 3113 log 1 service 'STANDBY'
Tue Nov 17 20:35:17 2009
Destination LOG_ARCHIVE_DEST_2 is UNSYNCHRONIZED
LGWR: Failed to archive log 1 thread 1 sequence 3466 (3113)
Tue Nov 17 20:35:18 2009
LGWR: Closing remote archive destination LOG_ARCHIVE_DEST_2: 'STANDBY' (error 3113)
(oradbt)
Tue Nov 17 20:35:18 2009
Errors in file /opt/oracle/admin/oradbt/bdump/oradbt_lgwr_319632.trc:
ORA-01041: internal error. hostdef extension doesn't exist
LGWR: Error 1041 closing archivelog file 'STANDBY'
LGWR: Error 1041 disconnecting from destination LOG_ARCHIVE_DEST_2 standby host 'STANDBY'