Showing posts from January, 2010

Oracle Enterprise Linux 5.4 Installation Setting on Sun Virtual Box

This in post i share my experience of installing Oracle Enterprise Linux 5.4 on Sun VirtualBox. Sun VirtualBox is freely available on their website you can download it free of cost. Sun VirtualBox is Presently, runs on Windows, Linux, Macintosh and OpenSolaris hosts and supports a large number of guest operating systems including but not limited to Windows (NT 4.0, 2000, XP, Server 2003, Vista, Windows 7), DOS/Windows 3.x, Linux (2.4 and 2.6), Solaris and OpenSolaris, and OpenBSD.

I have downloaded the VirtualBox 3.1.2 for Windows hosts and Install it on WindowXp.

As you seen in 1st screen shot i have already installed Redhat, SuSe Linux and XP on Sun Virtual Box. Now i am planning to Install Oracle Enterprise Linux 5.4 on Virtual Machine. For that click on New Button for the creation of new virtual machine.

In the 2nd Screen Shot define the name of machine on Name Field and select the type of OS from drop down list.

In the 3rd Screen Shot define the size of Base Memory. I have 2GB Physic…

Configure, Monitor and Use Oracle Database 11g Flashback

Configuring Flashback Database

Step # 1

Confirm that Flashback is enabled or not.

SQL> Select flashback_on from v$database;


Step # 2

Ensure that the database is in archivelog mode. Archivelog mode is a prerequisite for enabling Flashback Database. Confirm this by querying the V$DATABASE view
SQL> Select Log_mode from v$database;


If the database is not in Archivelog mode then above result is displayed.
Step # 3

Now switch Database to Archivelog mode

SQL> Shutdown Immediate;
SQL> Startup mount;
SQL> Alter Database Archivelog;

SQL> Select Log_mode from v$database;

Step # 4

Set up a flash recovery area.

The flash recovery area is the location for the flashback logs. You have no control over them other than setting the flash recovery area directory and limiting its size. It is controlled with two instance parameters: DB_RECOVERY_FILE_DEST specifies the…

Oracle Database 11g - Tablespace


A tablespace is where Oracle allocates space for your database. Without this you cannot create tables or store data.


For example:

DATAFILE ‘/opt/oracle/oradata/SID/test.dbf’ SIZE 10M;

DATAFILE ‘/opt/oracle/oradata/SID/test01.dbf’ SIZE 10M AUTOEXTEND ON NEXT 10M MAXSIZE 100M;


A bigfile Tablespaces is new to Oracle since Oracle 10g – a single datafile is allocated and it can be up to 8EB (Exabyte, a million terabytes) in size.

Why are these important?

• The maximum number of datafiles in an Oracle Database is limited (usually to 64K files) – think big here – think about a database for the Internal Revenue Service or NADRA (these are the Government Departments of Pakistan contain huge amount of data).

• A Bigfile Tablespace with 8K blocks can contain a 32 terabyte

Oracle Database 11g Recovery Manager (RMAN)

You can perform Oracle database backup in one of two ways. The first is the traditional user-managed backup method, which consists simply of using the operating system commands to copy the relevant files to a different location and/or to a tape device. The other method is RMAN, which is bundled with the database itself. With RMAN, you backup the database files from within the database.

A comprehensive set of backup and recovery tools that can streamline the backup and recovery of a database.

Cold Backup
A database cold backup is most likely the simplest way to make a backup of a database. A cold backup consists of making copies of the datafile, the control files, and the initialization parameter files while the database is shutdown. A cold backup is also known as a closed backup.

Cold backup may be taken when running the database in either NOARCHIELOG or ARCHIVELOG mode.

Hot Backup

A hot backup is similar to a cold backup, except that the backup is performed while the database is open and a…