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Cold backup vs hot backup [message #260240]

Fri, 17 August 2007 14:47

sroy
Messages: 38
Registered: July 2005

Member

I know the difference between rman cold backup and hot backup, but the size of the backup set created by the cold backup is bigger than hot backup. why is it so? I am starting to learn the various backup methods.

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Re: Cold backup vs hot backup [message #260243 is a reply to message #260240]

Fri, 17 August 2007 14:56

Michel Cadot
Messages: 68770
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

How do you take your backups?

Regards
Michel

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Re: Cold backup vs hot backup [message #260245 is a reply to message #260240]

Fri, 17 August 2007 15:05

sroy
Messages: 38
Registered: July 2005

Member

For cold backup, we do the following:
rman target /
shutdown immeidate;
startup mount;
backup database plus archivelog all;
alter database open;
exit

For the hot back, we execute:
rman target /
backup database plus archivelog all;
exit

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Re: Cold backup vs hot backup [message #260247 is a reply to message #260245]

Fri, 17 August 2007 15:22

DreamzZ
Messages: 1666
Registered: May 2007
Location: Dreamzland

Senior Member

Use COMPRESS option in backup command.

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Re: Cold backup vs hot backup [message #260248 is a reply to message #260245]

Fri, 17 August 2007 15:23

Michel Cadot
Messages: 68770
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Are you sure the difference does not come from the backup of archived logs and not the database itself?

Have look at v$backup% views.

Regards
Michel

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Re: Cold backup vs hot backup [message #260318 is a reply to message #260240]

Sat, 18 August 2007 06:19

sroy
Messages: 38
Registered: July 2005

Member

Yes, backup compressed backupset option is used in configuration settings.

The scripts looks exactly like that. I'll research $backup% views to see how cold backup creates such a huge backupsets. Anybody can experiment on a small test database and will be able to see the differences.

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Re: Cold backup vs hot backup [message #260322 is a reply to message #260318]

Sat, 18 August 2007 07:30

Michel Cadot
Messages: 68770
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Quote:

Anybody can experiment on a small test database and will be able to see the differences.

I don't understand, this is your database and your problem, you ask us to make experimentations for you?

Regards
Michel

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Re: Cold backup vs hot backup [message #260336 is a reply to message #260240]

Sat, 18 August 2007 10:05

sroy
Messages: 38
Registered: July 2005

Member

My experiment is done. Not sure if the the size of the backupsets look ok after cold backup. If someone happens to test his/her sample database he/she will probably notice the size after cold and hot backup.

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Re: Cold backup vs hot backup [message #260673 is a reply to message #260240]

Mon, 20 August 2007 12:15

sroy
Messages: 38
Registered: July 2005

Member

Found that there is no significant change in backupset size after running cold/hot backup on sample database. We are currently testing the new releases and watching their baselines as they go into production.

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