Oracle數據庫可以運行在兩種模式下:歸檔模式(archivelog)和非歸檔模式(noarchivelog)。
檢查歸檔模式命令：
SQL> archive log list Database log mode No Archive Mode Automatic archival Disabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 15 Current log sequence 17
設置歸檔模式：
SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 1258291200 bytes Fixed Size 1219160 bytes Variable Size 318768552 bytes Database Buffers 922746880 bytes Redo Buffers 15556608 bytes Database mounted. SQL> alter database archivelog; Database altered. SQL> alter database open; Database altered. SQL> archive log list; Database log mode Archive Mode Automatic archival Enabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 15 Next log sequence to archive 17 Current log sequence 17
如果需要停止歸檔模式，使用：alter database noarchivelog 命令。Oracle10g之前，你還需要修改初始化參數使數據庫處於自動歸檔模式。在pfile/spfile中設置如下參數：
log_archive_start = true
重啟數據庫此參數生效，此時數據庫處於自動歸檔模式。也可以在數據庫啟動過程中，手工執行：
archive log start
使數據庫啟用自動歸檔，但是重啟後數據庫仍然處於手工歸檔模式。10g使用db_recovery_file_dest來作為歸檔日志的存放地。
SQL> show parameter db_recovery NAME TYPE VALUE db_recovery_file_dest string /home/oracle/ora10g/flash_reco very_area/ db_recovery_file_dest_size big integer 20G
可以修改db_recovery_file_dest_size參數的大小
alter system set db_recovery_file_dest_size=21474836480
