rman backup should be smaller than the database ????

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newhorizon

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Nov 14, 2007, 10:22:27 AM11/14/07
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I am using RMAN backup.

When I get the hot RMAN backup using the following commands.


BACKUP DATABASE PLUS ARCHIVELOG;
BACKUP CURRENT CONTROLFILE;


I was expecting to see that the rman backup would be smaller since it
is copying the used blocks for the database. Should I shrink the
tables before the backup ?

fitzj...@cox.net

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Nov 14, 2007, 10:36:52 AM11/14/07
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You've neglected to consider that you're adding the archivelogs to the
mix; a BACKUP DATABASE should likely be smaller than the actual
database, but adding in the archivelogs expands that size
considerably.


David Fitzjarrell

Jerome Vitalis

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Nov 14, 2007, 10:40:52 AM11/14/07
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fitzj...@cox.net wrote:

>...but adding in the archivelogs expands that size
> considerably.


.. especially if there are lots of archived logs to backup *before* the
database backup.
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newhorizon

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Nov 14, 2007, 11:33:13 AM11/14/07
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I am glad put the command for the rman backup.

I really appreciate the comments on adding the achivelog in the
backupset.

What are your thoughts about shrinking the tables before the backup ?

fitzj...@cox.net

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Nov 14, 2007, 3:34:42 PM11/14/07
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I can't see that such an act would benefit you in terms of the backup
size. A shrink will only take away unused space (that above the HWM),
not free space located below the high water mark, so you might save a
few blocks of space per table, but it likely won't be appreciable.

I can't recommend it, but others may have differing opinions.


David Fitzjarrell

sybr...@hccnet.nl

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Nov 14, 2007, 3:43:47 PM11/14/07
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On Wed, 14 Nov 2007 08:33:13 -0800, newhorizon <mehme...@gmail.com>
wrote:

Why?
If you don't have the space to back-up buy disks.

--
Sybrand Bakker
Senior Oracle DBA

NetComrade

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Nov 14, 2007, 3:44:38 PM11/14/07
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On Wed, 14 Nov 2007 07:22:27 -0800, newhorizon <mehme...@gmail.com>
wrote:

Use compression in 10g
.......
We run Oracle 9iR2,10gR1/2 on RH4/RH3 and Solaris 10 (Sparc)
remove NSPAM to email

Maxim Demenko

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Nov 14, 2007, 4:20:21 PM11/14/07
to fitzj...@cox.net
fitzj...@cox.net schrieb:

I agree with your recommendation, however, if you refer to shrink in
sense of "ALTER TABLE ... SHRINK ...", then it does free space below HWM .

Best regards

Maxim

Peter Davoren

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Jun 30, 2022, 1:18:11 PMJun 30
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