Re: Rman vs. Manual Hot Backups

From: Howard J. Rogers <dba_at_hjrdba.com>
Date: Thu, 10 Jan 2002 22:09:34 +1100
Message-ID: <3c3d7629$0$1586$afc38c87@news.optusnet.com.au>

Because it's the catalog that tells RMAN what to do in a recovery. Without one, you are hoping that the target's controlfile is capable of storing all the necessary details -and the controlfile has a nasty habit of requiring old backup records to be over-written rather frequently (every 7 days is the default, IIRC). Total controlfile loss is a bit of bugger too, if there's no catalog.

Having said that, if you set controlfile_record_keep_time sensibly, and multiplex the controlfiles appropriately, the only real reason for using a catalog is that it allows you to store backup scripts. Given the subtleties of the RMAN syntax in 8 and 8i, that's worth doing. Given the simplicities of the syntax in 9i, it's not.

The catalog does, however, give you additional functionality (even in 9i) which is otherwise not available -such as doing TSPITRs. However, given that I've never needed to do a TSPITR in anger, I could live with the loss!

Regards
HJR

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"Keith Boulton" <kboulton_at_ntlunspam-world.com> wrote in message
news:0gc%7.5684$1s6.1114806_at_news6-win.server.ntlworld.com...


>

> "Ronald" <devnull_at_ronr.nl> wrote in message

> news:67ce88e7.0201082225.10d60e1f_at_posting.google.com...

> >

> > Don't forget to backup the rman catalog ! In case of a real disaster

> > you really need a recent backup catalog.

> > On my current site we have a production catalog that we backup open

> > and an extra rman catalog that we use to backup the catalog. The extra

> > catalog is taken offline for a conventional os backup. This we way

> > should always be able to get a working production catalog after we

> > loose it. We manage some 100 production db's, many of them 7*24.

>

> My normal preference is to use rman to backup the database to another disk

> and then use a normal backup program to backup that data to tape and

> maintain a catalog etc.

>

> In that circumstance, why do I need an rman catalog especially given the

> retarded decision to use an oracle database for it?

>

>

Received on Thu Jan 10 2002 - 05:09:34 CST