Re: Renaming datafiles on 7.1/OpenVMS

Hi James,
That knowledge base is correct though a bit unclear. You need to issue the command

alter database backup controlfile to '<a filename>' | trace

after any changes for like you just made. The reason for this is simple: if the database crashes and you loose the controlfile, you can't use an old backupped controlfile, because of the changes. The remnants of old filenames in the control file seem to be 'normal', I have been looking at similar dumps.

The concealed logicals: I now remember there has been an issue there. But then as far as I remember they changed that and logicals are stored untranslated in the control file. In that time I worked for a firm with a disaster recovery contract. The situation there was completely different, and hardcoded drivenames initially even prevented us from VMS getting up and running with our own software. If Oracle doesn't translate concealed logical, yes in that case I would use them to avoid problems with upgrading, plugging in new disks and disaster recovery.

Hth,
Sybrand Bakker, Oracle DBA

James Petts wrote:

> On Thu, 05 Nov 1998 20:28:34 +0100, Sybrand Bakker
> <postbus_at_sybrandb.demon.nl> wrote:
>
> >you need to rename the datafiles in the controlfile as well by issuing
> >alter database rename datafile 'xyz' to 'abc'. Of course you will need
> >to issue a startup nomount first (or was it mount). Anyway, the database
> >will definitely not open.
>
> Sorry, I didn't make myself clear eanough. I have already copied the
> files using the OS commands to the appropriate places, mounted the
> database, and used the ALTER DATABASE RENAME FILE <> to <> to change
> the datafiles as well.
>
> The reason for my question about the control file is that in
> RevealNet's DBA knowledge base it says that if you are renaming the
> system tablespace, or renaming multiple tablespaces at one you should
> 'Alter the database to backup the control file.'
>
> Also, when I do a hex dump of the control file I can still see the
> name of the original device on which the disk was stored.
>
> However, saying that, the database will start and appears to run fine.
>
> >Question: Does VMS still have concealed logicals for every disk? If so I
> >would recommend using them instead of hardcoded disknames like dra0:. I
> >had to rebuild a database once on a different system and hardcoded
> >disknames was one of the biggest issues.
>
> That is something I was wondering about. Does Oracle stop at the
> logical name, or will it try to resolve it to the actual device? I
> can't find anything about that in the documentation...
>
> Would you recommend using concealed logigals for the disk names?
>
> james
Received on Fri Nov 06 1998 - 12:00:26 CST