Re: RMAN sample script for Linux

> "In general, Oracle Corporation advises using a catalog when you manage
> multiple databases."
>
> Which can also be read to mean 'we don't advise it for a single database'.

I don't read it that way at all. That's your interpretation of the sentence. Let me give you a counter example.....A doctor tells you that if you have multiple warts, you should get them burned off. Does this mean that if you have a single wart, you should not get it burned off? Or, using a more mathematical approach, "A implies B" does not equate to "NOT A implies NOT B". In fact, is it highly possible that "NOT A implies B".

> And then, later, explicity they say:
>
> "Hence, unless you manage a network of databases, you may choose to avoid
> the overhead and use the control file as the exclusive repository of
> metadata"

Notice that your exact quote includes "...you *may* choose...". It does not say something like "...we recommend...". Even if you manage a network of databases, you may choose to avoid the overhead and use the control files as the exclusive repositories of metadata.

I really doubt that you will find any documentation that matches your blanket statement, "And, since this is 9i RMAN, Oracle is recommending running without a catalog database these days". Whether or not you use a Recovery Catalog is dictated by many factors. As can be seen from the 9i documentation
(http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96566/rcmquick.htm#442214), they include a section titled "Deciding Whether to Use RMAN with a Recovery Catalog". If your statement was true, then this section would be very short and say that they don't recommend using a Recovery Catalog. Instead, this section goes into detail on when it is a good idea to use a Recovery Catalog.

[quote from the docs]
Benefits of Using the Recovery Catalog as the RMAN Repository When you use a recovery catalog, RMAN can perform a wider variety of automated backup and recovery functions than when you use the control file in the target database as the sole repository of metadata. The following features are available only with a catalog:

You can store metadata about multiple target databases in a single catalog.
You can store metadata about multiple incarnations of a single target database in the catalog. Hence, you can restore backups from any incarnation.
Resynchronizing the recovery catalog at intervals less than the CONTROL_FILE_RECORD_KEEP_TIME setting, you can keep historical metadata. You can report the target database schema at a noncurrent time. You can store RMAN scripts in the recovery catalog. When restoring and recovering to a time when the database files that exist in the database are different from the files recorded in the mounted control file, the recovery catalog specifies which files that are needed. Without a catalog, you must first restore a control file backup that lists the correct set of database files. If the control file is lost and must be restored from backup, and if persistent configurations have been made to automate the tape channel allocation, these configurations are still available when the database is not mounted.
[/quote from the docs]

The docs go further to say

[quote from the docs]
When you use a control file as the RMAN repository, RMAN still functions effectively. If you do not use a catalog, read the section "Managing the RMAN Repository Without a Recovery Catalog". Specifically, make sure you:

Consider the costs of not using a recovery catalog, as described in "Understanding Catalog-Only Command Restrictions" Develop a strategy for backing up the repository, as described in "Backing Up and Restoring the Control File" [/quote from the docs]

The way I read the docs, it sounds to me like using a Recovery Catalog has its pros and cons and the DBA should be weigh each when making their configuration decisions. Blanket statements like "And, since this is 9i RMAN, Oracle is recommending running without a catalog database these days" are simply not true.

Cheers,
Brian

-- 
===================================================================

Brian Peasland
oracle_dba_at_remove_spam.peasland.com

Remove the "remove_spam." from the email address to email me.


"I can give it to you cheap, quick, and good. Now pick two out of
 the three"