Re: Differential incremental backups
- From: Robert Freeman <robertgfreeman@xxxxxxxxx>
- To: jkstill@xxxxxxxxx, oralrnr@xxxxxxxxx
- Date: Thu, 18 Mar 2010 09:44:32 -0700 (PDT)
Ok...
There are full backups and incremental backups. Full backups are of the entire
database.
Incremental backups have a full backup (level 0) and subsequent incremental
backups (level 1).
In earlier versions of RMAN multi-level incremental backups (level 1 through 5
if memory serves) were supported. Anything beyond a level 1 is deprecated
starting in 10g. You can still use them, but they are no longer supported.
There are two kinds of incremental backups (really three in 11g). They are:
differential
cumulative
Incrementally updated backups (11g).
Differential incremental backups are backups of changes since the last
incremental (level 1 backup), cumulative will backup all changed blocks since
the level 0. Thus, with a cumulative you only need one incremental backup
image, but it get's larger and takes longer over time.
Incrementally updated backups are a new 11g feature that allow you to merge the
level 1 backup into the level 0 base backup. Thus, at any time you only need 1
base and 1 incremental backup at any time. It differs from the incremental
backups in that the base backup is updated, so the level 1 backup will not be
as large or take as long as it otherwise would.
All this covered in my RMAN book....
RF
Robert G. Freeman
Master Principle Consultant, Oracle Corporation
Oracle ACE
Author:
Oracle Database 11g RMAN Backup and Recovery (Oracle Press) - ON ITS WAY SOON!
OCP: Oracle Database 11g Administrator Certified Professional Study Guide
(Sybex)
Oracle Database 11g New Features (Oracle Press)
Oracle Database 10g New Features (Oracle Press)
Other various titles
Blog: http://robertgfreeman.blogspot.com
________________________________
From: Jared Still <jkstill@xxxxxxxxx>
To: oralrnr@xxxxxxxxx
Cc: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
Sent: Thu, March 18, 2010 8:27:09 AM
Subject: Re: Differential incremental backups
At this point what I think you would find beneficial
is to stop speculating and start testing. :)
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
Oracle Blog: http://jkstill.blogspot.com
Home Page: http://jaredstill.com
On Thu, Mar 18, 2010 at 8:21 AM, Orlando L <oralrnr@xxxxxxxxx> wrote:
>
>
>Thanks. I wonder how it can restore to previous Friday if a base backup gets
>taken Sunday night. I thought it would restore base backup first and then
>apply incremental on the top of that base backup. I thought the backups taken
>before base backup were useless and cannot be used to restore to a point in
>time in last week, even if recovery window of 7 days is specified. ie, in this
>example, wanting to go back to last Friday on a given Monday, with a base
>backup on Sunday.
>>
>
>
>
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