Re: Best method to move Filesystems to RAW Devices.

Mark,
Thanks for the reply. We are on AIX 4.3. We are not changing hardware when we move on to RAW devices. Our entire hardware is going to remain same.
We feel dd is the fastest method of copying the files. But we need to figure out how many blocks
we should skip in raw devices.(point 2 in NOTES below). We still do not know how to do that. Metalink says if we use RMAN we do not need to
do any header calculation . Below is the article from metalink.. Thanks again for your suggestions.

goal: How to convert datafile from raw device to file system

a.. fact: Oracle Server - Enterprise Edition

a.. fix:

Use RMAN to move datafiles from raw devices to file system.

1. Connect to the database:

 $ sqlplus system/manager_at_orcl

2. Put the tablespace with the datafile, which should be converted, offline:

 SQL> alter tablespace test_ts offline;

3. Start rman and connect it to the database:

 $ rman nocatalog target rman/rman_at_orcl

4. Move the datafile to file system:

 RMAN> run {

 2> allocate channel c1 type disk;
 3> copy datafile '/dev/raw1' to '/u01/oradata/orcl/test_ts.dbf';
 4> }

5. Rename the moved datafile:

 SQL> alter database rename file '/dev/raw1' to '/u01/oradata/orcl/test_ts. dbf';

6. Put the tablespace back online:

 SQL> alter tablespace test_ts online;

Notes:

1. If you are using RMAN as the backup tool then a backup after the performed steps is recommended, because otherwise RMAN treats the copied file as a backup.
2. Usually Oracle datafiles are moved from filesystem to raw devices using the dd command. Using dd is the fastest method to accomplish it. However, it is necessary to know how many blocks to skip in the raw device (e.g. it is necessary to skip 64K on Tru64 Unix), so that the information necessary for the Operating System is not overwritten. The information on how many blocks to skip is different on the different platforms. Using RMAN there's no necessity to know such platform specific information.

.

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Thursday, September 19, 2002 5:28 PM

> Hi Nat,
>
> As long as you are not changing hardware platforms, you can use dd. (Of
> course, I assume you're on some flavor of unix, since you didn't mention
> OS.)
>
> You can just do 'dd if=/path/to/filsystem/datafile
> of=/path/to/raw/volume'.
>
> Of course, your database must be down.
>
> -Mark
>
> On Thu, 2002-09-19 at 14:38, Nat wrote:
> > We are planning to move to raw devices for all our existing file
systems.
> > Our database size is around 400 Gig. What is the recommended method that
you
> > guys feel is best as far as time
> > required to convert and ease of conversion.
> >
> > We feel we cannot use export - import as this may take more time for
> > conversion..
> > I checked many documents to find out the best method, there are few
> > suggestions to use RMAN to convert to raw.
> > seems it is fastest. At this point we have not configured RMAN on our
> > databases so this suggestion seems to be of no use for us.
> >
> > Please let me know, if any of you went through this exercise and any
> > suggestions and tips will be more beneficial,
> >
> > Thanks in advance,
> --
> --
> Mark J. Bobak
> Oracle DBA
> mark_at_bobak.net
> "It is not enough to have a good mind. The main thing is to use it
> well."
> -- Rene Descartes
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Mark J. Bobak
> INET: mark_at_bobak.net
>
> Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> San Diego, California -- Mailing list and web hosting services
> ---------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from). You may
> also send the HELP command for other information (like subscribing).
>

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Nat
  INET: Nat2710_at_hotmail.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).