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

From: DA Morgan <damorgan_at_x.washington.edu>
Date: Sun, 16 Jan 2005 18:08:32 -0800
Message-ID: <41eb1e18$1_1@127.0.0.1>

Thomas Kyte wrote:

> In article <beolu01umcqbaft3pmdmu5isst1c4as0bg_at_4ax.com>, Sybrand Bakker says...
>

>>On 16 Jan 2005 10:25:25 -0800, domenicg_at_hotmail.com (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?
>>>
>>>Domenic.
>>
>>Oracle requires 2 control files. It won't start without 2 control
>>files.
>>Mirroring only protects you against hardware failure.
>>It doesn't protect you against someone inadvertently deleting a
>>controlfile.
>>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

>
>
> Really?
>
> 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
>
> NAME TYPE VALUE
> ------------------------------------ ----------- ------------------------------
> control_file_record_keep_time integer 7
> control_files string /home/ora9ir2/oradata/ora9ir2/
> control01.ctl
> SQL>
>
>
> (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.

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


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Received on Sun Jan 16 2005 - 20:08:32 CST