Re: Backing up multiplexed control files?

"Rob Williamson" <robw_at_physics.umd.edu> wrote in message news:3A2EBD70.790AD73D_at_physics.umd.edu...
> My question is not answered in the documtation I believe.
> I want to know if I should bother to make an OS copy of each multiplexed
> control file, or is two or more copies of any one of them fine.
> In other words how parqanoid should I be?
> Can I trust that each multiplexed control file is identical? I have 3
> control files each on a separate disk ( multiplexed through the init.ora
> file ) should I copy all 3 of them to 2 different places ( ie 6 copies )
> or is that overkill and a waste of space?
> I am assuming copying one of the files to 2 or 3 different disks
> ( only 2 or 3 copies of one control file ).
>

It's not overkill... it's a good idea. You get Oracle doing multiple writes (thus minimising the risk of inadvertent corruption being introduced into all copies), you then have hardware mirroring -and mirrors can be broken, to aid particular types of recovery.

How important is your data? If the word 'very' appears anywhere in your answer, I suggest that no amount of paranoia is too much, provided you can afford it.

> Also is there a difference between the cold backup copy of of control
> files and the
> alter database backup controlfile to 'control.ctl'?
>

Yes, because the latter produces a read-consistent image of the control file whilst the database is in use. It would therefore be impossible to get such a file to be identical to a cold backup version (because at least one checkpoint would be done as part of the process of shutting down the database). If you mean are the two outputs *structurally* identical, then yes they are.

Regards
HJR
> Thanks in advance.
Received on Thu Dec 07 2000 - 13:21:19 CST