Parallel Backup of the Same Datafile (Intrafile parallel backup)

You probably already know that you can parallelize the backup by declaring more than one channel so that each channel becomes a RMAN session. However, very few realize that each channel can back up only one datafile at a time. So even through there are several channels, each datafile is backed by only one channel, somewhat contrary to the perception that the backup is truly parallel.

In Oracle Database 11g RMAN, the channels can break the datafiles into chunks known as "sections." You can specify the size of each section. Here's an example:

RMAN> run {
2>      allocate channel c1 type disk format '/backup1/%U';
3>      allocate channel c2 type disk format '/backup2/%U';
4>      backup 
5>      section size 500m 
6>      datafile 6;
7> }

This RMAN command allocates two channels and backs up the users' tablespace in parallel on two channels. Each channel takes a 500MB section of the datafile and backs it up in parallel. This makes backup of large files faster.

When backed up this way, the backups show up as sections as well.

RMAN> list backup of datafile 6;
... 

... 
    List of Backup Pieces for backup set 901 Copy #1
    BP Key  Pc# Status      Piece Name
    -------    ---  -----------      ----------
    2007    1   AVAILABLE   /backup1/9dhk7os1_1_1
    2008    2   AVAILABLE   /backup2/9dhk7os1_1_1
    2009    3   AVAILABLE   /backup1/9dhk7os1_1_3
    2009    3   AVAILABLE   /backup2/9dhk7os1_1_4

Note how the pieces of the backup show up as sections of the file. As each section goes to a different channel, you can define them as different mount points (such as /backup1 and /backup2), you can back them to tape in parallel as well.

However, if the large file #6 resides on only one disk, there is no advantage to using parallel backups. If you section this file, the disk head has to move constantly to address different sections of the file, outweighing the benefits of sectioning.

RMAN LEVEL 0 Backup

RUN {

ALLOCATE CHANNEL CH1 TYPE 'SBT_TAPE'; 

ALLOCATE CHANNEL CH2 TYPE 'SBT_TAPE'; 

ALLOCATE CHANNEL CH3 TYPE 'SBT_TAPE'; 

ALLOCATE CHANNEL CH4 TYPE 'SBT_TAPE';  

backup incremental level 0 filesperset 1 format '%d_LEVEL0_%s_%t_%p.dbf' database include current controlfile; 

sql 'alter system archive log current'; 

change archivelog all crosscheck; 

backup NOT BACKED UP 1 TIMES archivelog all  filesperset 1 format '%d_arch_%s_%t_%p.arc';

DELETE ARCHIVELOG ALL  BACKED UP 1 TIMES TO DEVICE TYPE sbt COMPLETED BEFORE 'SYSDATE-1/24';

RELEASE CHANNEL CH1; 

RELEASE CHANNEL CH2; 

RELEASE CHANNEL CH3; 

RELEASE CHANNEL CH4;  

}

what you mean by 11.2.0.3.0 (Major release.release.app release #.patch set.PSU)

11.2.0.3.0 : The first digit  is the major release number.  When we say 9i, 10g or 11g we mean the major release number

11.2.0.3.0 : This second digit is the maintenance release number. This is usually called only "release". For example when you say 11g Release 1 or 11g Release 2 in fact you are mentioning maintenance release number. Maintenance releases are full installations. It means that all files are replaced during upgrade. Maintenance releases contain bug fixes and new features for database.

11.2.0.3.0 : This third digit is the release number for Oracle application servers.  For database software, it should be 0.

11.2.0.3.0 : The fourth digit is called component specific release number. It shows the patch set version that has been applied to database. As of 11g, the patch sets are now full installations. They contain bug fixes and add new features to database. However the number of new features is not as high as maintenance releases'. Its scope is limited. This bugs fixed with this patch set are not listed here because applying a patchset is a full installation.

11.2.0.3.0 :The last digit is called platform specific release number. Patch set updates use this fifth number. A patch set update (PSU) is a collection of patches distributed 4 times a year by Oracle (every 3 months). They contain patches for most common bugs and security holes. They don't add a new feature to database. They are not full installations. Only faulty files on your database are replaced. Oracle recommends installing patch sets even if you haven't hit any of the bugs fixed in those patch sets

10G R2 New feature

- OCR can now be mirrored ,2 Copies Max
- Voting Disk can be mirrored ,3 Copies Max