From: <>
Date: Wed, 27 Aug 2008 21:24:42 +0200
Message-ID: <>

On Wed, 27 Aug 2008 12:01:19 -0700 (PDT), wrote:

>Sorry for the double post, but as we are reading and seeing BACKUPSET
>and BACKUPPIECE........we can see that a piece is part of a set. But,
>if you need to break up the set into pieces, why not just make smaller
>size sets??

A datafile can not span multiple backupsets. A datafile can span multiple backuppieces. You could configure 2G backuppieces (max filesize for 32-bit files on some Unixes) and have a backupset of unlimited size.

>Also, how does this relate to FILESPERSET?

All files in a set will be

a) simultaneously opened
b) simultaneously backupped
c) get multiplexed in one backupset, so 1 block for datafile 1 is
followed by one block for datafile 2 etc.

If you have all your datafiles on few disks, NOT configuring filesperset (Oracle by default tries to back up as much as possible) create an I/O bottleneck.
You could argue filesperset always needs to be 1.

>We're all new to this.....
>Thank you


Sybrand Bakker
Senior Oracle DBA
Received on Wed Aug 27 2008 - 14:24:42 CDT

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