Path: news.cambrium.nl!textnews.cambrium.nl!feeder1.cambriumusenet.nl!feed.tweaknews.nl!212.27.60.9.MISMATCH!proxad.net!feeder2-2.proxad.net!newsfeed.news2me.com!news.astraweb.com!border2.newsrouter.astraweb.com!not-for-mail From: "Bob Jones" Newsgroups: comp.databases.oracle.server References: <7fe4c1bc-8f2d-47c2-b8e7-1b13c6d6eb3e@k30g2000yqf.googlegroups.com> Subject: Re: Rman level 0 incremental backup – why restore needs older backups? Date: Sun, 26 Jul 2009 11:03:09 -0500 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 X-RFC2646: Format=Flowed; Original Lines: 62 Message-ID: <00b3bcf7$0$23895$c3e8da3@news.astraweb.com> Organization: Unlimited download news at news.astraweb.com NNTP-Posting-Host: 02aa9807.news.astraweb.com X-Trace: DXC=Oh2nlk=TRf:hn]AcMfkkb9L?0kYOcDh@:T=47B=V8C_4dj@1^E2]bi2b2h^OndObjZ\hh__?M2P?ZVfhdR5 Xref: news.cambrium.nl > > I am on Oracle 10.2.0.3 on HP UNIX 11.2 > > > I have always been doing rman level 0 backup using commands like: > > backup as compressed backupset > > level 0 incremental > > Format 'dbfile_%U%_%t' > > database; > > > I thought level 0 incremental is full backup, i.e., does backup of > > every block in the file. > > My backup was done on July 20,2009 6:00PM and ended on 6:30PM. > > Now I am doing point in time recovery to restore database until July > > 20, 6:31PM. > > Restore should only need backup files from July 20, 2009 6:00PM > > onwards, But for some reason > > restore requires backup files as old as from July 10, 2009. > > I thought level 0 incremental does full backup, i.e, it does not need > > older backups. > > > Can any one explain why? Does it have to do with use of compressed? > > > I will think in I just did level 0 (without incremental), then for > > sure I will not need older backups. Using level 0 compressed will do > > the same, i.e., full backup without requiring older backups. > > Well the simple answer is that you are thinking incorrectly. > > http://download.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkup00... > > When rman starts a level 0 incremental it checks to see when the last > level 0 was taken and gets blocks changed since that level 0. > > If it cannot see/find a previous level 0 incremental backup then it > gets a full backup. > > One strategy is to move older backups off to tape ( sometimes without > even using rman or telling rman about that ) ... deleting the old > backup ... doing a cross check ... then doing a level 0 incremental. > > Bottom line you need to both understand what you are doing and test > your backup strategy so you don't surprise yourself when you actually > have an important recovery operation needed to perform.- Hide quoted > text - > > - Show quoted text - All the documenation I have read is: A level 0 incremental backup is the base backup for subsequent incremental backups. It copies all blocks containing data, backing the datafile up into a backup set just as a full backup would. The only difference between a level 0 incremental backup and a full backup is that a full backup is not included in an incremental strategy. That is after taking full backup , you can’t perform incremental backup over. _______________________________________________________________ That's correct. You just need to make sure your backup is complete and accessible.