幫同學處理一個物化檢視問題，順便發現alert日誌中有以下報錯：

Errors in file /u01/app/oracle/diag/rdbms/abce/abce/trace/abce_ora_381201.trc:
ORA-01580: error creating control backup file /dbbak/abce/crtl_bak/snapcf_abce.f
ORA-27040: file create error, unable to create file
Linux-x86_64 Error: 2: No such file or directory

控制檔案備份失敗，提示檔案或者目錄不存在。

首先檢視rman的預設配置。

RMAN> show all;

using target database control file instead of recovery catalog
RMAN configuration parameters for database with db_unique_name abce are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/dbbak/abce/crtl_bak/snapcf_abce.f';

RMAN> 

重點看這一行：

CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/dbbak/abce/crtl_bak/snapcf_abce.f';

一般snapshot的format應該是快照控制檔案的絕對路徑，這裡的配置格式是對的。

然後檢查一下目錄是否存在，通過檢查發現，目錄crtl_bak壓根不存在。

順便看了一下這個機器的備份日誌，發現備份早就出問題了。