rman備份,控制文件丟失的解決辦法
2024-07-21 02:35:35
供稿：網友
情況描述
客戶報告數據庫故障，新來的系統治理員誤操作。刪掉了一些文件。
詢問：
刪掉了那些文件？請大致描述一下數據庫備份情況.
答曰：
所有重要數據文件，所有控制文件。數據庫原來是歸檔模式，用rman備份數據，而rman 使用控制文件。
幸運的是，最后一次rman full 備份是包括了控制文件在內。系統沒有設定自動備份控制文件．現在狀況是數據庫無法啟動．
不用說，客戶的備份方案不夠完善，但是這時候再去說這些話責備用戶有事后諸葛亮之嫌，用戶是上帝，不要去得罪他。還有，客戶有Full備份（雖然不是自動備份控制文件，這樣無法用常規(guī)的恢復步驟來進行恢復）。這對我們來說是個絕對的好消息。
下面我們通過一次模擬操作來演示這個問題的解決辦法。
解決過程
首先，用控制文件作數據庫系統的全備份：
代碼:------------------------黑色部分是敏感信息，須加以注重----------------------------------------------------
C:WUTemp>rman target /
Recovery Manager: Release 9.2.0.1.0 - PRodUCtion.
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
connected to target database: DEMO (DBID=3272375326)
RMAN> run {
2> allocate channel C1 type disk;
3> backup full tag 'FullBackup' format 'd:/KDE/%d_%u_%s_%p.dbf' database include current controlfile;
4> sql ' alter system archive log current';
5> release channel C1;
6> }
using target database controlfile instead of recovery catalog
allocated channel: C1
channel C1: sid=15 devtype=DISK
Starting backup at 18-JUL-04
channel C1: starting full datafile backupset
channel C1: specifying datafile(s) in backupset
including current SPFILE in backupset
including current controlfile in backupset
input datafile fno=00001 name=D:/ORACLE/ORADATA/DEMO/SYSTEM01.DBF
input datafile fno=00002 name=D:/ORACLE/ORADATA/DEMO/UNDOTBS01.DBF
input datafile fno=00004 name=D:/ORACLE/ORADATA/DEMO/EXAMPLE01.DBF
input datafile fno=00009 name=D:/ORACLE/ORADATA/DEMO/XDB01.DBF
input datafile fno=00005 name=D:/ORACLE/ORADATA/DEMO/INDX01.DBF
input datafile fno=00008 name=D:/ORACLE/ORADATA/DEMO/USERS01.DBF
input datafile fno=00003 name=D:/ORACLE/ORADATA/DEMO/DRSYS01.DBF
input datafile fno=00006 name=D:/ORACLE/ORADATA/DEMO/ODM01.DBF
input datafile fno=00007 name=D:/ORACLE/ORADATA/DEMO/TOOLS01.DBF
channel C1: starting piece 1 at 18-JUL-04
channel C1: finished piece 1 at 18-JUL-04
piece handle=D:/KDE/DEMO_01FR79OT_1_1.DBF comment=NONE
channel C1: backup set complete, elapsed time: 00:01:17
Finished backup at 18-JUL-04
sql statement: alter system archive log current
released channel: C1
--如上所示，我們做了一次數據庫的Full備份．備份片中包括控制文件．注重上面輸出內容的黑體部分．我們在后面的恢復操作中會用到．
模擬錯誤，關掉實例，刪掉所有的控制文件和所有的.DBF文件。然后starup會看到如下的出錯信息:
SQL> startup
ORACLE instance started.
Total System Global Area 152115804 bytes
Fixed Size 453212 bytes
Variable Size 100663296 bytes
Database Buffers 50331648 bytes
Redo Buffers 667648 bytes
ORA-00205: error in identifying controlfile, check alert log for more info
查看alert Log,應該是系統找不到控制文件．現在情形和客戶問題一致．不過在繼續(xù)講述之前，我們還需要介紹一點背景知識．
背景知識：
在Oracle 816 以后的版本中,Oracle提供了一個包:DBMS_BACKUP_RESTORE.DBMS_BACKUP_RESTORE 包是由dbmsbkrs.sql 和 prvtbkrs.plb 這兩個腳本創(chuàng)建的.catproc.sql 腳本運行后會調用這兩個包.所以是每個數據庫都有的這個包是Oracle服務器和操作系統之間IO操作的接口.由恢復治理器直接調用。
而且據說這兩個腳本的功能是內建到Oracle的一些庫文件中的.
由此可見，我們可以在數據庫 nomount 情況下調用這些package ,來達到我們的恢復目的。在dbmsbkrs.sql 和prvtbkrs.plb 這兩個腳本中有具體的說明文檔，出于篇幅問題，就不一一加以翻譯了，但在下面會直接引用一些原文說明。
要害的內容有：
FUNCTION deviceAllocate(
type IN varchar2 default NULL
,name IN varchar2 default NULL
,ident IN varchar2 default NULL
,noio IN boolean default FALSE
,params IN varchar2 default NULL )
RETURN varchar2;
-- Describe the device to be used for sequential I/O. For device types where
-- only one process at a time can use a device, this call allocates a device
-- for exclusive use by this session. The device remains allocated until
-- deviceDeallocate is called or session termination. The device can be used
-- both for creating and restoring backups.
--
-- Specifying a device allocates a context that exists until the session
-- terminates or deviceDeallocate is called. Only one device can be specified
-- at a time for a particular session. Thus deviceDeallocate must be called
-- before a different device can be specified. This is not a limitation since
-- a session can only read or write one backup at a time.
--
-- The other major effect of allocating a device is to specify the name space
-- for the backup handles (file names). The handle for a sequential file does
-- not necessarily define the type of device used to write the file. Thus it
-- is necessary to specify the device type in order to interpret the file
-- handle. The NULL device type is defined for all systems. It is the file
-- system supplied by the Operating system. The sequential file handles are
-- thus normal file names.
--
-- A device can be specified either by name or by type.
-- If the type is specified but not the name, the system picks an
-- available device of that type.
-- If the name is specified but not the type, the type is determined
-- from the device.
-- If neither the type or the name is given, the backups are files in
-- the operating system file system.
-- Note that some types of devices, optical disks for example, can be shared
-- by many processes, and thus do not really require allocation of the device
-- itself. However we do need to allocate the context for accessing the
-- device, and we do need to know the device type for proper interpretation
-- of the file handle. Thus it is always necessary to make the device
-- allocation call before making most other calls in this package.
--
-- Input parameters:
-- type
-- If specified, this gives the type of device to use for sequential
-- I/O. The allowed types are port specific. For example a port may
-- support the type "TAPE" which is implemented via the Oracle tape
-- API. If no type is specified,
it may be implied by specifying a
-- particular device name to allocate. The type should be allowed to
-- default to NULL if operating system files are to be used.
--
-- name
-- If specified, this names a particular piece of hardware to use for
-- accessing sequential files. If not specified, any available
-- device of the correct type will be allocated. If the device cannot
-- be shared, it is allocated to this session for exclusive use.
-- The name should be allowed to default to NULL if operating system
-- files are to be used.
--
-- ident
-- This is the users identifier that he uses to name this device. It
-- is only used to report the status of this session via
-- dbms_application_info. This value will be placed in the CLIENT_INFO
-- column of the V$SESSION table, in the row corresponding to the
-- session in which the device was allocated. This
