Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Usenet -> c.d.o.server -> Re: One control file/redo member with ASM ok?

Re: One control file/redo member with ASM ok?

From: DA Morgan <>
Date: Mon, 17 Jan 2005 14:23:10 -0800
Message-ID: <41ec3ac1$1_1@>

Thomas Kyte wrote:

> In article <41eb1e18$1_1_at_127.0.0.1>, DA Morgan says...

>>Thomas Kyte wrote:
>>>In article <>, Sybrand Bakker says...
>>>>On 16 Jan 2005 10:25:25 -0800, (Domenic) wrote:
>>>>>Is it acceptable to use one control file and one redo log member only
>>>>>(per group) on a database using ASM, where ASM is doing the mirroring?
>>>>>What's Oracle's recommendation/opinion on this? Wouldn't two control
>>>>>files and two redo members per group be overkill when ASM is doing the
>>>>>mirroring also?
>>>>Oracle requires 2 control files. It won't start without 2 control
>>>>Mirroring only protects you against hardware failure.
>>>>It doesn't protect you against someone inadvertently deleting a
>>>>Also the controlfile is usually only a few Mb's big. It would be very
>>>>strange to try to save a few Mb's and instead increase the risk
>>>>someone blows up your database.
>>>>Sybrand Bakker, Senior Oracle DBA
>>>SQL> startup pfile=initora9ir2.ora
>>>ORACLE instance started.
>>>Total System Global Area 269554828 bytes
>>>Fixed Size 451724 bytes
>>>Variable Size 201326592 bytes
>>>Database Buffers 67108864 bytes
>>>Redo Buffers 667648 bytes
>>>Database mounted.
>>>Database opened.
>>>SQL> show parameter control
>>>------------------------------------ ----------- ------------------------------
>>>control_file_record_keep_time integer 7
>>>control_files string /home/ora9ir2/oradata/ora9ir2/
>>> control01.ctl
>>>(they have the control files mirrored via ASM mirroring)
>>I have mixed feelings on this one.
>>While technically you are correct ... advising someone that they can do
>>this invites a very dangerous behaviour. Companies may suffer greviously
>>because someone reads this as Tom Kyte saying it is ok. And even I would
>>gleefully do what you recommend or what I assume you have sanctioned.
> I didn't say "do this", I just said "it is not true that you need two -- and you
> do understand that ASM has made it so that there are two transparently"
> ASM mirrors or triple mirrors.  There is redundancy there already.
> Oracle does not require two control files. 
> Oracle does suggest that the minimum should be two.

I understood but only because I have read the doc. And while I have never personally had a corrupted control file under ASM it still gives me the shakes.

See you in Victoria.

Daniel A. Morgan
University of Washington
(replace 'x' with 'u' to respond)

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- The #1 Newsgroup Service in the World! >100,000 Newsgroups
---= East/West-Coast Server Farms - Total Privacy via Encryption =---
Received on Mon Jan 17 2005 - 16:23:10 CST

Original text of this message