What is the difference between redundancy and recovery for retention window?

Hi all

I'm still trying to get a grip on this concept of planning RMAN backup.

I recently came across a situation like this.

I have backups on a redundancy of 1.

I have instance1, who had a job of GRID to run backups RMAN as follows

Database incremental level = 0 a week at sea at 02:30
I have backups daily, incremental level = 1 every night
I have backups of the log of the archives through the day.

What happened, was apparently on a TUE some time, the development team remove data in almost all of the tables in the schema.
The this didn't discover until noon or so on Wednesday.

I went to try to restore... and RMAN could not do. I had found a SNA for early TUES, they did... but I got the following error:

RMAN > RUN
2 > {}
3 > SET up to this THAT SNA 4590383198282.
4 > RESTORE database;
5 > RECOVER DATABASE;
{6 >}

executing command: SET until clause

From restoration to the 28 April 10
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID = 639 device type = SBT_TAPE
channel ORA_SBT_TAPE_1: NMO v4.5.0.0
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID = 638 type device = DISK

File number of the data file = 1 name=+DATADG/instance1/datafile/system.284.697137287
RMAN-00571: ===========================================================
RMAN-00569: = ERROR MESSAGE STACK FOLLOWS =.
RMAN-00571: ===========================================================
RMAN-03002: failure of the command restore at 2010-04-28 15:53
ORA-01180: cannot create the data file 1
ORA-01110: data file 1: '+ DATADG/instance1/datafile/system.284.697137287 '.

What I did... of research, it seems that since I don't have a level 0 incremental of before, he could not reset the database in time. Precedent has been removed since, I guess I had a redundancy of 1.

So, I thought that I had a week of backup they way I put it... but that assumes that the errors are found fairly quickly before the next level = 0 backup.

I want at least 1 to 1.5 weeks of worth of backups. I have the problem that we do have many tapes in rotation, so I can't go because too long..may 2 x weeks at the top.

I'm revising my strategy, but I am confused that I read about the difference between retention RMAN setting with window of recovery / redundancy.

Can someone give me an explanation how do you understand? I read on the web and in books to oracle, and for some reason, it is not clear to me what is the best way to go... especially when I see this window of redundancy and recovery can affect?

Thank you in advance,

Cayenne

Redundancy = 1 means rman will mark any more old than the backup of the last full or incremental backup of level 0 as obsolete. So it is very likely that the backup that you need for this restore has been removed after work Wednesday morning.

The recovery window will tell rman to keep (or not obsolete brand) all necessary backups to restore to any point in time in the recovery window.

Bjoern

Tags: Database

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