Re: RMAN v Control Files

On Sun, 16 Feb 2003 20:33:23 +0800, Gary Mandaracas wrote:

> Thanks for your feedback.
>
> Your right, Data Protector is just HP's backup software which integrates
> with Oracle and other software.
>
> We are currently on 8i, I don't know if your comment on the catalogue
> database no longer being required still applies.
>

I had hoped I made myself clear, but obviously not. The recommendation to dispense with the catalog is a 9i one. The reason is that RMAN now stores 'persistent configuration parameters' in the control file of the target database, meaning that backup becomes a one-line command 'backup database;'. Not too complicated!! But in 8i, there were no persistent configuration parameters, meaning that the number of channels, the destination of the backup, the file name, the parallelism, and so on and on, had to be specified at run time. Which means that the backup command is a full-blown entity with a scripting language from hell. Therefore you probably want to write a backup script. And scripts can't be stored in anything other than a catalog database.

Hence the business of 'complicated backups': if you still need to specify 68 different variables every time you backup, you probably still need to script. And at that point, a catalog is still needed, even in 9i.

Basic incrementals and fulls can still be done with single line commands (backup database incremental level 2; for example) in 9i. So mere incrementalism doesn't warrant a catalog.

But in 8i, I'd say a catalog was warranted where there was more than a couple of databases.

> I'm not sure what constitutes a complicated backup strategy but we have four
> databases on 8i and take two incremental backups during the day plus a full
> online backup at night - each database is around 30Gb.
>

Peanuts, frankly. Quite why you need to take two incrementals during the day, I can't imagine. Your data volumes are not particularly large: I'd be astonished if your DML rates were sufficient to warrant that sort of approach. But whatever: you make your own decisions on these thing. Now I realise you're on 8i, I'd say the guy recommended no catalog has been infected with the 9i bug, and needs to be a bit more aware. He's cutting corners.

Regards
HJR
> Cheers
>
> Gary
>
Received on Mon Feb 17 2003 - 04:14:16 CST