How to Recover Oracle 10G Database Using Data Files-Redo logs-Control files during OS failure


Hi Guys,
              Many times we have seen that when the operating system get failure due to something miss happening or miss handled with the system and the system contains the very important databases which you don't wanna loose at any cost and you do not have any backup for that. So I am writing this technique how to recover the Oracle 10G database on this situation. It is very interesting & the easiest way to recover the database.If something like this happened with you then don't worry go with the below mentioned steps and restore your database:
For recovering the database we have to need following files.

1.      Database datafiles
2.      Control files
3.      Redologs
4.      Parameter files
5.      Other database related files
Database datafiles:
Database data files are physical files which are stored on secondary memory. These files are used to store the physical data. Database data files are only written by the Oracle DB Writer. These physical data files are associated with Oracle Tablespaces which are logical containers for tables and indexes. Database datafiles are basically located on path D:\oracle\ product\10.2.0\oradata\sid\

Example of datafiles:

 DR01.DBF, INDX01.DBF, TOOLS01.DBF, TEMP01.DBF, SYSTEM01.DBF, USERS01.DBF, RBS01.DBF & .ORA
Control Files:
The Control files of the database is a binary file that contains the essential information about the database. The control files contains the information like database name, database log files.Without
control files Oracle cannot works it is mandatory for database.Because the control files are so important & Oracle allows you to maintain duplicate copies of the control files.
These control files are located on D:\product\10.2.0\oradata\sid\
Example of Control Files:
CONTROL01.CTL, CONTROL02.CTL,CONTROL03.CTL
 Online redo logs concepts:

Online redo logs like a tape recorder that records every change in the Oracle database. As modification occur, they are continuously recorded in the online redo logs.
 Oracle requires two online redo logs which are assigned to the database. Oracle writes the redo to the first log and when the first log is full then Oracle will switch to the second log and write the same redo logs.
Redologs are also located on the same path where the control & datafiles resides d:\ oracle\ product\10.2.0\oradata \sid\
 Examples of Redologs:
REDO01.LOG, REDO02.LOG, REDO03.LOG 
Oracle Parameter file Concepts:
 The parameter file (also called init.ora) contains configuration information for the database to use at startup time. The parameter file you configure how much RAM the database is use, where to find the control files, where to write trace file,alert file and a whole host of other information. Many times the oracle database will not start without a parameter file. Oracle also allows you to have a manual parameter file (called a PFILE) or a server-side parameter file (called a SPFILE). Parameter file is located on path D:\oracle\ product\10.2.0\admin\sid\pfile\ init.ora

Steps for recovering the database:  

1. After installing the fresh operating system you have to installed oracle 10G on the same drive again where the Oracle were installed earlier for the easy recovery of the database.
2. But before new installation of oracle engine take the backup of all required files which are mentioned below.

init.ora from D:\oracle\ product\10.2.0\admin\sid\pfile\,
pwdSID from D:\ oracle\product\10.2.0\db_1\database\.
Redologs(REDO01.LOG, REDO02.LOG, REDO03.LOG),
Control files (CONTROL01.CTL, CONTROL02.CTL,CONTROL03.CTL ) &
.DBF(DR01.DBF,INDX01.DBF,TOOLS01.DBF,TEMP01.DBF, SYSTEM01.DBF, USERS01.DBF,RBS01.DBF)&.ORA files from D:\oracle \ product\10.2.0\oradata\ 
3.  Now place the all backup files on below mentioned path 

Place Redologs,Control files & .DBF & .ORA files on location D:\oracle\ product\10.2.0 \oradata\
init.ora on location D:\oracle\ product\10.2.0\admin\sid\pfile\   and
PWDSID.ora on location  D:\ oracle\product\10.2.0\db_1\database\. 

4. And then restart the oracle services and run the SQL console.
Hope this will help You.
Have a nice Day....

Regards,
Sampan

Comments

  1. 21st Century Software Solutions14 May 2014 at 19:52

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