Oracle Server - Question - RMAN 8i - Catalog or control file?

Author

Question - RMAN 8i - Catalog or control file?

2005-07-28, 1:25 pm

Hey, all.

I'm configuring RMAN under 8i (AIX 5.2), and have been told by my team
lead that the preference is not to use a catalog, simply because it's
just one more point of failure / db to back up / etc.

So my 'task' is to roll out RMAN with the control file only option.

I'm trying to make sure that this is really the best choice.

At this point, I am also seeing compelling reasons that I SHOULD use
the catalog - for example, under 8i, the 'persistent configuration
parameters' are not retained - which means that scripting would be more
cumbersome, especially with multiple databases.

If these parameters can be provided in a standard shell script, then I
guess that's okay (haven't quite gotten to that point yet) - but what
I'm currently looking for is an outline of those bits of functionality
that are lacking when using the control file option.

According to the docs, this functionality includes "Stored scripts" and
"restore and recovery when the control file is lost or damaged."

FWIW, we have two 8i servers, one of which has 3 dbs and one of which
has one.

We also have a 9i server - I'm a little more comfortable with the
control file option under 9i, as it seems like there's less
functionality lost.

Does anyone know of any 'summary' articles which discuss the Catalog vs
Control file question, and might assist a DBA in deciding which option
is best for their environment??

Tx,

DW

2005-07-28, 1:25 pm

Well, predictably, soon after posting I ran into the relevant section
in the doc.

I'll consider myself duly slapped around. ;)

Joel Garry

2005-07-28, 8:23 pm

No reason to beat yourself up, it's a legitimate question. As you've
found, there are only a few things catalog can give you, and only your
business needs decision makers can decide if they are important.

Of course, being on 8i is an indicator that the decision makers have an
odd view of things.

You might also look into the OMS. It can make pretty pictures for
management to evaluate your db performance. And once you have that db,
you might as well add RMAN to it, eh? It's really not all that hard to
add another small db when you already have several.

For most smaller sites, nocatalog is just fine IMHO. You probably want
to backup controfile to trace, too. So, within my rman backup script I
have sql "alter database backup controlfile to trace"; and then after
rman is done:

(cd ${ORACLE_BASE}/admin/${ORACLE_SID}/udump; cp $(ls -t $(fgrep -l
'CREATE CONTROLFILE' *.trc)|head -1) ${FLASH_AREA}/controlfile.txt )
# This gets the backup controlfile to trace from udump that is done
during the
# backup. So a cleanup of udump is ok whenever desired, and you don't
have
# to worry about tracing every time you make a change to the db.

I also don't like removing archived logs as soon as they are backed up,
I'd rather wait a couple backup cycles if I have the space.

jg
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