Re: converting from "cooked" to "raw" oracle database

stre..._at_yahoo.co.uk wrote:
> i'm working on a database which consists of datafiles in filesystems
> (referred to as cooked in some technical documents). i want to look
at
> the performance difference with all the files raw i.e. using logical
> volumes to store the data. i know its possible to backup raw files
> using the dd command. what i'm interested in finding
out/understanding
> is how to perform the opposite process i.e. convert from a 'cooked'
to
> 'raw' storage system for an existing instance containing data. can i
> use a dd command to copy data from file to logical volume? is an
> export/import the only option? i'm going to be performing a number of
> tests myself and will post findings here. any other knowledge on
> subject appreciated.

Take a look at this ...

http://www.oracle.com/technology/deploy/performance/pdf/TWP_Oracle_HP_files.pdf

No you want to use either RMAN or something hardware based to copy raw files ( bcv breaking mirrors on emc etc ). Yes you can use dd to copy raw you don't really want to go there.

Copying cooked to raw ... my questions would be ...

How much data do you have? How much time do you have?

Any reason to avoid using export?

Take a look at that paper first. Start educating yourself on raw. Metalink has some semi useful info if you have access ... otherwise google is your friend.

The learning curve for raw is big but things like rman and hardware based options make it (somewhat less).

Who will be maintaining? Just you or a team? What happens if you leave?

Those are other questions to think about. Received on Fri Apr 15 2005 - 20:05:44 CDT