查看数据库状态，数据库为归档模式
[email protected] hey~J->archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 1
Next log sequence to archive 1
Current log sequence 1
注 归档路径为参数USE_DB_RECOVERY_FILE_DEST指定的路径，也就是快速恢复区路径
修改数据库为非归档模式（开启、关闭归档模式都需要在mount模式下进行）
[email protected] hey~J->shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
[email protected] hey~J->startup mount;
ORACLE instance started.
Total System Global Area 830930944 bytes
Fixed Size 2257800 bytes
Variable Size 541068408 bytes
Database Buffers 281018368 bytes
Redo Buffers 6586368 bytes
Database mounted.
[email protected] hey~J->alter database noarchivelog;
Database altered.
[email protected] hey~J->archive log list;
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 1
Current log sequence 1
[email protected] hey~J->select status from v$instance;
STATUS
------------
MOUNTED
[email protected] hey~J->alter database archivelog;
Database altered.
[email protected] hey~J->archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 1
Next log sequence to archive 1
Current log sequence 1
[email protected] hey~J->alter database open;
Database altered.
数据库启动归档以后，特别要注意的是，归档文件所放的目录是否还有剩余空间，如果空间不足了，那么就会导致数据库hang的现象，因为当redo日志切换以后，日志将归档，日志是循环使用的，如果循环到未归档的redo文件以后，那么数据库就会出现hang的情况，等待日志的归档。所以，剩余空间和过期的归档日志都是必须要维护的。