Re: Why is a backup of the controlfiles needed

From: Rene Nyffenegger <rene.nyffenegger_at_gmx.ch>
Date: 26 Aug 2004 16:36:08 GMT
Message-ID: <slrncis49m.fg.rene.nyffenegger@zhnt60m34.netarchitects.com>

In article <IwnXc.12482$S35.9178_at_newssvr29.news.prodigy.com>, Mark Bole wrote:

> Rene Nyffenegger wrote:
> 

>> In article <xfnXc.12475$1Y4.7457_at_newssvr29.news.prodigy.com>, Mark Bole wrote:
>>

>>>Albert Albani wrote:
>>>
>>>
>>>>I don't understand why backups of controlfiles are needed in an
>>>>archivelog hotbackuped environment. The controlfiles should be multiplexed,
>>>>so if one failes, there is always a good one around that can be copied.
>>>>
>>>>Is there a scenario in which a backup of a controlfile is truly needed?
>>>>
>>>>Thanks
>>>>Albert
>>>
>>>They may be multiplexed, but they're still all on the same server. What 
>>>if your server dies?

>>
>>
>>
>> Then again, the online redo logs are on the same server as well. And I'd think
>> it would be disasterous, if they were gone forever, if my server (hw) died.
>>
>> Rene
>>
>>

> 
> Actually, you are not supposed to ever back up your on-line redo logs. 
> In an incomplete recovery situation (server crash) you would open your 
> database resetlogs on the new server.

I didn't mean to imply that backups of online redo logs should be taken.

My point was: If I want to be able to recover until the very last executed commit, I need to make sure that I have access to at least one member of each group of the online redo log, no matter what happens to the server. If one hard disk crashes, bad, but not disasterous, because there is a copy of it on another harddisk. But if it is possible to get at least one copy of the online redo log, I can equally get one copy of a control file.

However, your point is, as I understand it, if the server dies badly, you can at least make an incomplete recovery more easily because the control file had been backed up.

Rene

-- 
  Rene Nyffenegger
  http://www.adp-gmbh.ch/

Received on Thu Aug 26 2004 - 11:36:08 CDT