Re: student question: incremental backups (level 0 and level 1)
Date: Fri, 27 Jun 2008 07:43:29 -0700 (PDT)
Holger Baer wrote:
> The documentation is a little bit clearer (http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/rcmconc1005.htm#sthref241):
> Multilevel Incremental Backups
> RMAN can create multilevel incremental backups. Each incremental level is denoted by a value of 0 or 1. A level 0 incremental backup, which is the base for
> subsequent incremental backups, copies all blocks containing data.
> The only difference between a level 0 incremental backup and a full backup is that a full backup is never included in an incremental strategy.
> The important point to note:
> - a level 0 incremental backup copies all blocks containing data
> This does not mean all blocks that *ever* contained data, think of truncate table for example. So the OP is right to express his doubts about the wording,
> even if it's not in the sense he originally meant. Another example: drop a table/index/partition and you're likely to to have lots of blocks that once contained
> data but now don't. They shouldn't (and to the best of my knowledge don't) get backed up.
The metalink note: 134214.1 states clearly that if a block *EVER*
(i.e. if an oracle process *EVER* wrote to it), that block will be backed up.
Only empty blocks are skipped in the backup, where empty means the block was never written to *ever*.
Anurag Received on Fri Jun 27 2008 - 09:43:29 CDT