Re: Differential incremental backups
Date: Thu, 18 Mar 2010 09:44:32 -0700 (PDT)
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:
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....
Robert G. Freeman
Master Principle Consultant, Oracle Corporation Oracle ACE
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
From: Jared Still <jkstill_at_gmail.com> To: oralrnr_at_gmail.com
Cc: "oracle-l_at_freelists.org" <oracle-l_at_freelists.org> 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. :)
On Thu, Mar 18, 2010 at 8:21 AM, Orlando L <oralrnr_at_gmail.com> 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.