一．問題說明操作系統： RedHat 5.8

數據庫： 11.2.0.3

2節點RAC.

使用RMAN 備份的時候，報如下錯誤：

ORA-00245: control file backup failed;target is likely on a local file system

這個問題只存在Oracle 11gR2以后的RAC 環境。

二．ORA-245 觸發條件在以下的5種環境下，會出現ORA-00245的錯誤。

2.1 RAC 環境下，自動備份備份控制文件，會因為ORA-245的錯誤而失敗

Autobackup of controlfile in RMAN isfailing with error:RMAN-571: ===========================================================RMAN-569: =============== ERROR MESSAGE STACK FOLLOWS ===============RMAN-571: ===========================================================RMAN-3009: failure of Control File and SPFILE Autobackup command on ORA_DISK_1 channel at 10/27/2010 12:13:31ORA-245: control file backup Operation failed

2.2 RAC 環境下，備份控制文件到非共享的本地路徑，也會失敗SQL> ALTER DATABASE BACKUP CONTROLFILETO '/u01/backup/control.bk' REUSE*ERROR at line 1:ORA-245: control file backup operation failed

2.3 在RAC 環境下，創建standby controlfile 到非共享的本地路徑也會失敗SQL> alter database create standby controlfileas '/home/oracle/renostdbycntrl.ctl';

alter database create standby controlfileas '/home/oracle/renostdbycntrl.ctl'*ERROR at line 1:ORA-245: control file backup operation failed

2.4 在RAC 環境下，copy 當前的控制文件到本地路徑channel ch1: starting datafile copycopying current control fileRMAN-571: ===========================================================RMAN-569: =============== ERROR MESSAGE STACK FOLLOWS ===============RMAN-571: ===========================================================RMAN-3009: failure of backup command on 10/07/2011 11:36:42 channel at ch1ORA-245: control file backup operation failed

2.5 RAC 環境下，controlfile 快照備份到非共享位置，RMAN 備份也會失敗RMAN-00571:========================================================RMAN-00569: ============ ERROR MESSAGE STACK FOLLOWS =============RMAN-00571: =========================================================RMAN-03009: failure of resync command on default channel at 03/13/2012 10:19:41

ORA-00245: control file backup operation failed

三. 錯誤原因From 11gR2onwards, the controlfile backup happens without holding the controlfileenqueue. For non-RAC database, this doesn't change anything. But for RACdatabase, due to the changes made to the controlfile backup mechanism in 11gR2,any instance in the cluster may write to the snapshot controlfile. Due to thissnapshot controlfile need to be visible to all instances.--從Oracle11gR2 開始，在備份控制文件時，不在需要鎖住controlfile enqueue。對于非RAC 的數據庫， 沒有任何改變，但對于RAC 數據庫，因為控制文件備份機制的改變，集群中的任何instance 可以需要寫入到快照控制文件，因此snapshot controlfile需要對所有實例是可見的。In RACenvironment any form of controlfile backup may fail with ORA-0245 if thelocation of the Snapshot Controlfile is not a shared location.--在RAC 環境下，如果snapshot controlfile 不在共享的位置，控制文件任何形式的都可能報ORA-245的錯誤。The backup ofthe controlfile actualy makes a backup of the SNAPSHOT controlfile. TheSnapshot controlfile is created when the controlfile is about to be backed up.--控制文件的備份實際上是生成一個SNAPSHOT controlfile，在備份時生成快照文件。The Snapshotcontrolfile is a read-consistent copy of the controlfile.--快照控制文件是控制文件的一個read-consistent copy。The snapshotcontrolfile MUST be accessible by all nodes of a RAC database, if the snapshotcontrolfile does not reside on a shared device error will be raised at the timeof RMAN backup while taking snapshot of controlfile.--快照控制文件必須能被所有節點訪問，如果快照控制不是存放在共享設備上，那么在RMAN 進行控制文件的快照備份時就會報錯。This applies to backingup controlfile using sqlplus / having autobackup of controlfileconfigured on non-shared location.ORA-245 error message description----------------------------------------00245, 00000, "control file backup operation failed"*Cause: Failed to create a control file backup because some PRocess signaled anerror during backup creation.*Action: Check alert files for further information. This usually happens becausesome process could not access the backup file during backup creation. Anyprocess of any instance that starts a read/write control file transaction musthave an access to the backup control file during backup creation.四. 解決方法4.1. 檢查快照控制文件位置RMAN> show snapshot controlfile name;4.2 配置snapshot controlfile 到共享位置RMAN> CONFIGURE SNAPSHOT CONTROLFILENAME TO '<shared_disk>/snapcf_<DBNAME>.f';如果使用了ASM，就指定到對應的ASM disk group：RMAN> CONFIGURE SNAPSHOT CONTROLFILENAME TO '+<DiskGroup>/snapcf_<DBNAME>.f';參考文檔：In RAC environment from 11.2 onwards BackupOr Snapshot controlfile needs to be in shared location [ID 1472171.1]RMAN backup fails with Ora-00245 AndRman-08132 [ID 1365484.1]RMAN BACKUP TO LOCAL DEVICE WITH SNAPSHOTON SHARED FAILS ORA-00245 [ID 1516654.1]本篇文章來源于 linux公社網站(www.linuxidc.com)  原文鏈接：http://www.linuxidc.com/Linux/2013-02/79773p2.htm